diff --git a/crates/engine/src/export.rs b/crates/engine/src/export.rs
index 6a9e9147c..edc4760cf 100644
--- a/crates/engine/src/export.rs
+++ b/crates/engine/src/export.rs
@@ -297,8 +297,20 @@ fn watermark_cell_glyphs(
 
 /// Draw `wm` onto `img` (straight alpha blending of the encoded values).
 pub fn draw_watermark(img: &mut Rgba8, wm: &Watermark) {
+    blend_watermark(img, wm, 1.0);
+}
+
+/// Draw `wm` onto `img`, a preview of an export whose short edge is `export_short_edge` pixels.
+/// The smallest text size and shadow offset scale with the preview, so it looks like the file.
+pub fn draw_watermark_preview(img: &mut Rgba8, wm: &Watermark, export_short_edge: usize) {
+    let short = img.width.min(img.height);
+    let scale = if export_short_edge == 0 { 1.0 } else { short as f32 / export_short_edge as f32 };
+    blend_watermark(img, wm, scale);
+}
+
+fn blend_watermark(img: &mut Rgba8, wm: &Watermark, floor_scale: f32) {
     let width = img.width;
-    watermark_coverage(img.width, img.height, wm, crate::fonts::CRAFT_FONTS, |x, y, k, col| {
+    watermark_coverage(img.width, img.height, wm, crate::fonts::CRAFT_FONTS, floor_scale, |x, y, k, col| {
         let p = &mut img.data[y * width + x];
         for c in 0..3 {
             p[c] = (p[c] as f32 + (col[c] as f32 - p[c] as f32) * k).round() as u8;
@@ -311,14 +323,14 @@ pub fn draw_watermark(img: &mut Rgba8, wm: &Watermark) {
 pub fn draw_watermark_deep(img: &mut DeepImage, wm: &Watermark) {
     let (width, trc) = (img.width, img.space.trc());
     match &mut img.samples {
-        DeepSamples::U16(v) => watermark_coverage(img.width, img.height, wm, crate::fonts::CRAFT_FONTS, |x, y, k, col| {
+        DeepSamples::U16(v) => watermark_coverage(img.width, img.height, wm, crate::fonts::CRAFT_FONTS, 1.0, |x, y, k, col| {
             let i = (y * width + x) * 3;
             for c in 0..3 {
                 let p = v[i + c] as f32;
                 v[i + c] = (p + (col[c] as f32 * 257.0 - p) * k).round().clamp(0.0, 65535.0) as u16;
             }
         }),
-        DeepSamples::F32(v) => watermark_coverage(img.width, img.height, wm, crate::fonts::CRAFT_FONTS, |x, y, k, col| {
+        DeepSamples::F32(v) => watermark_coverage(img.width, img.height, wm, crate::fonts::CRAFT_FONTS, 1.0, |x, y, k, col| {
             let i = (y * width + x) * 3;
             for c in 0..3 {
                 let target = trc.decode(col[c] as f32 / 255.0);
@@ -330,12 +342,14 @@ pub fn draw_watermark_deep(img: &mut DeepImage, wm: &Watermark) {
 
 /// Lay out `wm` on a `width × height` image and call `blend(x, y, coverage × opacity, colour)` for
 /// every covered pixel (shadow pass first). `craft` is [`crate::fonts::CRAFT_FONTS`] (a parameter
-/// so tests can render without it).
+/// so tests can render without it). `floor_scale` is this image's size over the exported file's
+/// (1 when drawing the file itself): the 6 px minimum text size is a minimum in the file.
 fn watermark_coverage(
     width: usize,
     height: usize,
     wm: &Watermark,
     craft: &'static [crate::fonts::CraftFont],
+    floor_scale: f32,
     mut blend_px: impl FnMut(usize, usize, f32, [u8; 3]),
 ) {
     use ab_glyph::{Font, PxScale, ScaleFont, point};
@@ -355,7 +369,7 @@ fn watermark_coverage(
         Vec::new()
     };
     let short = width.min(height) as f32;
-    let px = (wm.size.clamp(0.005, 0.5) * short).max(6.0);
+    let px = (wm.size.clamp(0.005, 0.5) * short).max(6.0 * floor_scale);
     let mut glyphs = Vec::new();
     let mut x = 0.0f32;
     let mut y = 0.0f32;
@@ -459,7 +473,7 @@ fn watermark_coverage(
         blend_px(gx as usize, gy as usize, (cov * a).clamp(0.0, 1.0), col);
     };
     let passes: &[(f32, [u8; 3], f32)] =
-        if wm.shadow { &[((px * 0.05).max(1.0), [0, 0, 0], 0.45), (0.0, wm.color, 1.0)] } else { &[(0.0, wm.color, 1.0)] };
+        if wm.shadow { &[((px * 0.05).max(floor_scale), [0, 0, 0], 0.45), (0.0, wm.color, 1.0)] } else { &[(0.0, wm.color, 1.0)] };
     for &(off, col, a) in passes {
         for (face, g, rotation) in &glyphs {
             if let Some(o) = fonts.get(*face).and_then(|font| font.outline_glyph(g.clone())) {
@@ -1996,6 +2010,27 @@ mod tests {
         assert!(ExportOptions::from_json(&serde_json::json!({"watermark": ""})).watermark.is_none());
     }
 
+    /// A preview keeps the export's 6 px minimum text size as a share of the photo: a watermark
+    /// clamped to 6 px in a 150 px export covers the same share of a 600 px preview.
+    #[test]
+    fn watermark_preview_scales_the_minimum_text_size() {
+        let wm = Watermark { text: "LightCraft".into(), size: 0.01, opacity: 1.0, shadow: false, ..Default::default() };
+        let rows = |img: &Rgba8| (0..img.height).filter(|&y| (0..img.width).any(|x| img.get(x, y)[0] > 64)).count() as f32;
+        let mut export = Rgba8::new(200, 150);
+        draw_watermark(&mut export, &wm);
+        let mut preview = Rgba8::new(800, 600);
+        draw_watermark_preview(&mut preview, &wm, 150);
+        let mut unscaled = Rgba8::new(800, 600);
+        draw_watermark(&mut unscaled, &wm);
+        let (export_share, preview_share) = (rows(&export) / 150.0, rows(&preview) / 600.0);
+        assert!((preview_share - export_share).abs() < 0.02, "export {export_share}, preview {preview_share}");
+        assert!(rows(&unscaled) < rows(&preview) / 2.0, "the unscaled 6 px floor would draw it too small");
+        // drawn at the export's own size, the preview is the export
+        let mut same = Rgba8::new(200, 150);
+        draw_watermark_preview(&mut same, &wm, 150);
+        assert_eq!(same.data, export.data);
+    }
+
     fn vertical_japanese() -> Watermark {
         let options =
             ExportOptions::from_json(&json!({"watermark": {"text": "日本語", "vertical": true, "size": 0.1, "shadow": false, "opacity": 1.0}}));
@@ -2019,7 +2054,7 @@ mod tests {
         assert_eq!(watermark_fonts(&[]).len(), 1, "Inter only");
         for wm in [vertical_japanese(), Watermark { text: "LightCraft 日本語".into(), ..Watermark::default() }] {
             let mut covered = 0usize;
-            watermark_coverage(400, 300, &wm, &[], |_, _, k, _| covered += usize::from(k > 0.0));
+            watermark_coverage(400, 300, &wm, &[], 1.0, |_, _, k, _| covered += usize::from(k > 0.0));
             assert!(covered > 0, "{:?} draws something", wm.text);
         }
     }
@@ -2056,7 +2091,7 @@ mod tests {
             ..Default::default()
         };
         let mut pixels = Vec::new();
-        watermark_coverage(400, 300, &wm, craft, |x, y, k, _| {
+        watermark_coverage(400, 300, &wm, craft, 1.0, |x, y, k, _| {
             if k > 0.5 {
                 pixels.push((x, y));
             }
@@ -2081,7 +2116,7 @@ mod tests {
                 ..Default::default()
             };
             let mut pixels = vec![0.0f32; 400 * 300];
-            watermark_coverage(400, 300, &wm, craft, |x, y, k, _| pixels[y * 400 + x] = k);
+            watermark_coverage(400, 300, &wm, craft, 1.0, |x, y, k, _| pixels[y * 400 + x] = k);
             assert!(pixels.iter().any(|&k| k > 0.0));
             pixels
         };
diff --git a/crates/ui-egui/locales/de.json b/crates/ui-egui/locales/de.json
index aa24e0f10..0bbca889e 100644
--- a/crates/ui-egui/locales/de.json
+++ b/crates/ui-egui/locales/de.json
@@ -793,6 +793,7 @@
   "List Presets": "Vorgaben auflisten",
   "List Profiles": "Profile auflisten",
   "List this folder in Local from now on": "Diesen Ordner ab jetzt unter „Lokal“ auflisten",
+  "Loading preview…": "Vorschau wird geladen…",
   "Local": "Lokal",
   "Local folders": "Lokale Ordner",
   "Local library — no cloud account needed": "Lokale Bibliothek — kein Cloud-Konto erforderlich",
@@ -1071,6 +1072,7 @@
   "Preview Build Progress": "Fortschritt der Vorschauerstellung",
   "Preview only": "Nur Vorschau",
   "Preview size": "Vorschaugröße",
+  "Preview unavailable": "Vorschau nicht verfügbar",
   "Previews": "Vorschauen",
   "Previous Photo": "Vorheriges Foto",
   "Print": "Drucken",
diff --git a/crates/ui-egui/locales/es.json b/crates/ui-egui/locales/es.json
index c4f2e8357..5c2aa4e33 100644
--- a/crates/ui-egui/locales/es.json
+++ b/crates/ui-egui/locales/es.json
@@ -754,6 +754,7 @@
   "List Presets": "Enumerar ajustes preestablecidos",
   "List Profiles": "Enumerar perfiles",
   "List this folder in Local from now on": "Mostrar esta carpeta en Local a partir de ahora",
+  "Loading preview…": "Cargando vista previa…",
   "Local": "Local",
   "Local folders": "Carpetas locales",
   "Local library — no cloud account needed": "Biblioteca local: no requiere cuenta en la nube",
@@ -1024,6 +1025,7 @@
   "Preview Build Progress": "Progreso de generación de vistas previas",
   "Preview only": "Solo vista previa",
   "Preview size": "Tamaño de la vista previa",
+  "Preview unavailable": "Vista previa no disponible",
   "Previews": "Vistas previas",
   "Previous Photo": "Foto anterior",
   "Print": "Imprimir",
diff --git a/crates/ui-egui/locales/fr.json b/crates/ui-egui/locales/fr.json
index f3422bc0a..72bed4d81 100644
--- a/crates/ui-egui/locales/fr.json
+++ b/crates/ui-egui/locales/fr.json
@@ -754,6 +754,7 @@
   "List Presets": "Lister les préréglages",
   "List Profiles": "Lister les profils",
   "List this folder in Local from now on": "Afficher désormais ce dossier dans Local",
+  "Loading preview…": "Chargement de l'aperçu…",
   "Local": "Local",
   "Local folders": "Dossiers locaux",
   "Local library — no cloud account needed": "Bibliothèque locale : aucun compte cloud nécessaire",
@@ -1024,6 +1025,7 @@
   "Preview Build Progress": "Progression de la génération des aperçus",
   "Preview only": "Aperçu uniquement",
   "Preview size": "Taille de l'aperçu",
+  "Preview unavailable": "Aperçu indisponible",
   "Previews": "Aperçus",
   "Previous Photo": "Photo précédente",
   "Print": "Imprimer",
diff --git a/crates/ui-egui/locales/ja.json b/crates/ui-egui/locales/ja.json
index a7a3a32ef..56e1b9e63 100644
--- a/crates/ui-egui/locales/ja.json
+++ b/crates/ui-egui/locales/ja.json
@@ -561,6 +561,7 @@
   "List History": "履歴を一覧表示",
   "List Presets": "プリセットを一覧表示",
   "List Profiles": "プロファイルを一覧表示",
+  "Loading preview…": "プレビューを読み込み中…",
   "Locate Photo": "写真の場所を指定",
   "Lock": "ロック",
   "Lock Crop Aspect": "切り抜きの縦横比を固定",
@@ -640,6 +641,7 @@
   "Press keys…": "キーを押してください…",
   "Preview Build Progress": "プレビュー作成の進行状況",
   "Preview only: editing the camera's embedded JPEG": "プレビューのみ：カメラの埋め込みJPEGを編集中",
+  "Preview unavailable": "プレビューを表示できません",
   "Previous Photo": "前の写真",
   "Profile Browser": "プロファイルブラウザー",
   "Profile Menu": "プロファイルメニュー",
diff --git a/crates/ui-egui/locales/pt-br.json b/crates/ui-egui/locales/pt-br.json
index c3d9a8d78..911a56f49 100644
--- a/crates/ui-egui/locales/pt-br.json
+++ b/crates/ui-egui/locales/pt-br.json
@@ -762,6 +762,7 @@
   "List Presets": "Listar predefinições",
   "List Profiles": "Listar perfis",
   "List this folder in Local from now on": "Listar esta pasta em Local a partir de agora",
+  "Loading preview…": "Carregando prévia…",
   "Local": "Local",
   "Local folders": "Pastas locais",
   "Local library — no cloud account needed": "Biblioteca local — não precisa de conta na nuvem",
@@ -1035,6 +1036,7 @@
   "Preview only": "Somente pré-visualização",
   "Preview only: editing the camera's embedded JPEG": "Somente prévia: editando o JPEG incorporado da câmera",
   "Preview size": "Tamanho da pré-visualização",
+  "Preview unavailable": "Prévia indisponível",
   "Previews": "Pré-visualizações",
   "Previous Photo": "Foto anterior",
   "Print": "Imprimir",
diff --git a/crates/ui-egui/locales/ru.json b/crates/ui-egui/locales/ru.json
index bf9974740..7ca4e25c9 100644
--- a/crates/ui-egui/locales/ru.json
+++ b/crates/ui-egui/locales/ru.json
@@ -627,6 +627,7 @@
   "List Presets": "Список пресетов",
   "List Profiles": "Список профилей",
   "List this folder in Local from now on": "Показывать эту папку в «Локальном» и дальше",
+  "Loading preview…": "Загрузка просмотра…",
   "Local": "Локальное",
   "Local folders": "Локальные папки",
   "Local library — no cloud account needed": "Локальная библиотека — учётная запись в облаке не нужна",
@@ -855,6 +856,7 @@
   "Preview Build Progress": "Ход создания просмотров",
   "Preview only": "Только просмотр",
   "Preview size": "Размер просмотра",
+  "Preview unavailable": "Просмотр недоступен",
   "Previews": "Просмотры",
   "Previous Photo": "Предыдущее фото",
   "Print": "Печать",
diff --git a/crates/ui-egui/locales/uk.json b/crates/ui-egui/locales/uk.json
index c73c05b93..0b1107418 100644
--- a/crates/ui-egui/locales/uk.json
+++ b/crates/ui-egui/locales/uk.json
@@ -109,6 +109,7 @@
   "Lines +/−": "Рядки +/−",
   "Lines added": "Додані рядки",
   "Lines deleted": "Видалені рядки",
+  "Loading preview…": "Завантаження перегляду…",
   "Lock": "Заблокувати",
   "Merged PRs": "Об’єднані PR",
   "Model": "Модель",
@@ -120,6 +121,7 @@
   "No matching commands": "Немає відповідних команд",
   "No model credits were built into this copy.": "У цю копію не вбудовано дані про використані моделі.",
   "Press keys…": "Натисніть клавіші…",
+  "Preview unavailable": "Перегляд недоступний",
   "Radial": "Радіальний",
   "Random": "Випадковий",
   "Real name": "Справжнє ім’я",
diff --git a/crates/ui-egui/locales/zh-hans.json b/crates/ui-egui/locales/zh-hans.json
index 21fa4e4e9..ae3a905b8 100644
--- a/crates/ui-egui/locales/zh-hans.json
+++ b/crates/ui-egui/locales/zh-hans.json
@@ -548,6 +548,7 @@
   "Lines +/−": "行数 +/−",
   "Lines added": "新增行数",
   "Lines deleted": "删除行数",
+  "Loading preview…": "正在加载预览…",
   "Lock": "锁定",
   "Lock Crop Aspect": "锁定裁剪长宽比",
   "Locked": "已锁定",
@@ -594,6 +595,7 @@
   "Presets and profiles": "预设和配置文件",
   "Press keys…": "请按键…",
   "Preview only: editing the camera's embedded JPEG": "仅预览：正在编辑相机内嵌的 JPEG",
+  "Preview unavailable": "预览不可用",
   "Proof copy created": "已创建校样副本",
   "Quit Anyway": "仍然退出",
   "Quit with unsaved changes?": "有未保存的更改，确定退出吗？",
diff --git a/crates/ui-egui/locales/zh-hant.json b/crates/ui-egui/locales/zh-hant.json
index d2e0a30c2..f9a5d26b4 100644
--- a/crates/ui-egui/locales/zh-hant.json
+++ b/crates/ui-egui/locales/zh-hant.json
@@ -548,6 +548,7 @@
   "Lines +/−": "行數 +/−",
   "Lines added": "新增行數",
   "Lines deleted": "刪除行數",
+  "Loading preview…": "正在載入預覽…",
   "Lock": "鎖定",
   "Lock Crop Aspect": "鎖定裁切長寬比",
   "Locked": "已鎖定",
@@ -594,6 +595,7 @@
   "Presets and profiles": "預設集與描述檔",
   "Press keys…": "請按鍵…",
   "Preview only: editing the camera's embedded JPEG": "僅預覽：正在編輯相機內嵌的 JPEG",
+  "Preview unavailable": "無法使用預覽",
   "Proof copy created": "已建立校樣副本",
   "Quit Anyway": "仍要結束",
   "Quit with unsaved changes?": "有未儲存的變更，確定要結束嗎？",
diff --git a/crates/ui-egui/src/headless.rs b/crates/ui-egui/src/headless.rs
index d0104f7de..89ac1542e 100644
--- a/crates/ui-egui/src/headless.rs
+++ b/crates/ui-egui/src/headless.rs
@@ -1762,6 +1762,29 @@ mod tests {
         assert!(w1 < 700.0, "{w1}");
     }
 
+    /// With a watermark on, the Export dialog shows the first photo with the watermark on it.
+    #[test]
+    fn export_dialog_previews_the_watermark() {
+        let mut h = demo([1400.0, 900.0]);
+        let t = Duration::from_secs(10);
+        h.request("engine.execute", json!({"command": "dialog.export", "params": {}}), t);
+        let preview = |h: &mut Headless| {
+            let r = h.request("ui.widgets", json!({}), t);
+            r["result"].as_array().and_then(|a| a.iter().find(|w| w["id"] == "image:exportWatermarkPreview")).map(|w| w["rect"].clone())
+        };
+        h.settle(SETTLE);
+        assert!(preview(&mut h).is_none(), "no preview without a watermark");
+        if let Some(crate::state::Dialog::Export { opts, .. }) = &mut h.app.ui.dialog {
+            opts.watermark = Some(lightcraft_engine::export::Watermark { text: "© LightCraft".into(), ..Default::default() });
+        }
+        let t0 = Instant::now();
+        while preview(&mut h).is_none() && t0.elapsed() < Duration::from_secs(30) {
+            h.step();
+        }
+        let rect = preview(&mut h).expect("the watermark preview is shown");
+        assert!(rect[2].as_f64().unwrap() > 50.0 && rect[3].as_f64().unwrap() > 50.0, "{rect}");
+    }
+
     #[test]
     fn export_dialog_runs_in_the_background() {
         let mut h = demo([1200.0, 900.0]);
diff --git a/crates/ui-egui/src/panels/dialogs.rs b/crates/ui-egui/src/panels/dialogs.rs
index aa287c952..bf70eeb63 100644
--- a/crates/ui-egui/src/panels/dialogs.rs
+++ b/crates/ui-egui/src/panels/dialogs.rs
@@ -54,6 +54,104 @@ pub(crate) fn rename_preview(
     (read(&rows), total)
 }
 
+/// Largest size of the Export dialog's watermark preview (points; fits the 380 pt dialog).
+const WM_PREVIEW_MAX: egui::Vec2 = egui::vec2(348.0, 200.0);
+
+/// The Export dialog's watermark preview: the first exported photo's thumbnail with the watermark
+/// drawn on it as the file will have it at size `resize` (`None` = full size). The thumbnail
+/// (cached, else rendered) is made on a worker thread once per photo and catalog change; the
+/// watermark is redrawn on a copy only when it or the output size changes, which is quick at
+/// thumbnail size, so the preview follows the sliders.
+fn watermark_preview(
+    app: &mut LightcraftApp,
+    ui: &mut egui::Ui,
+    wm: &lightcraft_engine::export::Watermark,
+    resize: Option<lightcraft_engine::export::Resize>,
+) {
+    use std::hash::{Hash, Hasher};
+    type Base = std::sync::Arc<std::sync::Mutex<Option<Result<lightcraft_raster::Rgba8, String>>>>;
+    type Shown = (u64, lightcraft_engine::export::Watermark, usize, egui::TextureHandle);
+    let t = Tokens::get(ui.ctx());
+    let Some(&id) = app.session.targets(&json!({})).first() else { return };
+    let Some(photo) = app.session.catalog.photo(id).cloned() else { return };
+    let (out_w, out_h) = lightcraft_engine::export::output_size(&photo, &lightcraft_engine::export::ExportOptions { resize, ..Default::default() });
+    let export_short = out_w.min(out_h);
+    let mut h = std::collections::hash_map::DefaultHasher::new();
+    (id, app.session.catalog.revision).hash(&mut h);
+    let key = h.finish();
+    let ctx = ui.ctx().clone();
+    let (base_id, shown_id) = (egui::Id::new("export-wm-preview-base"), egui::Id::new("export-wm-preview-shown"));
+    let base = match ctx.data(|d| d.get_temp::<(u64, Base)>(base_id)) {
+        Some((k, base)) if k == key => base,
+        _ => {
+            let base: Base = Default::default();
+            match app.session.thumb_job(id, 512) {
+                Some(job) => {
+                    let (out, repaint) = (base.clone(), ctx.clone());
+                    let work = move || {
+                        let r = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| job.run().rendered.map(|r| r.image)))
+                            .unwrap_or_else(|_| Err("the preview failed unexpectedly".into()));
+                        *out.lock().unwrap_or_else(std::sync::PoisonError::into_inner) = Some(r);
+                        repaint.request_repaint();
+                    };
+                    #[cfg(not(target_arch = "wasm32"))]
+                    if let Err(e) = std::thread::Builder::new().name("lc-watermark-preview".into()).spawn(work) {
+                        log::warn!("watermark preview: {e}");
+                    }
+                    #[cfg(target_arch = "wasm32")]
+                    work();
+                }
+                None => *base.lock().unwrap_or_else(std::sync::PoisonError::into_inner) = Some(Err("no such photo".into())),
+            }
+            ctx.data_mut(|d| d.insert_temp(base_id, (key, base.clone())));
+            base
+        }
+    };
+    let shown = ctx.data(|d| d.get_temp::<Shown>(shown_id));
+    let tex = match shown {
+        Some((k, w, s, tex)) if k == key && &w == wm && s == export_short => tex,
+        _ => {
+            let photo_px = match &*base.lock().unwrap_or_else(std::sync::PoisonError::into_inner) {
+                Some(Ok(img)) => Ok(img.clone()),
+                Some(Err(e)) => Err(Some(e.clone())),
+                None => Err(None),
+            };
+            let mut img = match photo_px {
+                Ok(img) => img,
+                Err(e) => {
+                    let note = if e.is_some() { "Preview unavailable" } else { "Loading preview…" };
+                    let r = ui.label(egui::RichText::new(crate::i18n::tr(note)).color(t.text_dim));
+                    if let Some(e) = e {
+                        r.on_hover_text(e);
+                    }
+                    return;
+                }
+            };
+            lightcraft_engine::export::draw_watermark_preview(&mut img, wm, export_short);
+            // shown through the monitor profile like every other preview
+            if let Some(d) = app.renderer.display()
+                && let Err(e) = d.profile.from_srgb(&mut img)
+            {
+                log::warn!("display profile: {e}");
+            }
+            let color = std::sync::Arc::new(egui::ColorImage::from_rgba_unmultiplied([img.width, img.height], &img.as_bytes()));
+            let tex = match shown {
+                Some((.., mut tex)) => {
+                    tex.set(color, egui::TextureOptions::LINEAR);
+                    tex
+                }
+                None => ctx.load_texture("export-wm-preview", color, egui::TextureOptions::LINEAR),
+            };
+            ctx.data_mut(|d| d.insert_temp(shown_id, (key, wm.clone(), export_short, tex.clone())));
+            tex
+        }
+    };
+    let size = tex.size_vec2();
+    let scale = (WM_PREVIEW_MAX.x.min(ui.available_width()) / size.x).min(WM_PREVIEW_MAX.y / size.y);
+    let r = ui.vertical_centered(|ui| ui.add(egui::Image::new((tex.id(), size * scale)))).inner;
+    crate::widgets::register(ui.ctx(), "image:exportWatermarkPreview", r.rect);
+}
+
 /// About dialog tabs: (widget id suffix, label). The credits come from `crate::credits`.
 pub const ABOUT_TABS: &[(&str, &str)] = &[("about", "About"), ("contributors", "Contributors"), ("models", "Models")];
 
@@ -629,6 +727,10 @@ pub fn show(app: &mut LightcraftApp, ctx: &egui::Context) {
                     if ui.checkbox(&mut wm_on, crate::i18n::tr("Watermark")).changed() {
                         opts.watermark = wm_on.then(|| lightcraft_engine::export::Watermark { text: "© ".into(), ..Default::default() });
                     }
+                    let wm_shown = opts.watermark.clone();
+                    if let Some(wm) = &wm_shown {
+                        watermark_preview(app, ui, wm, (!*full_size).then_some(*resize));
+                    }
                     if let Some(wm) = &mut opts.watermark {
                         // text, or a graphic (a logo with transparency)
                         let mut graphic = !wm.image.is_empty() || ui.data(|d| d.get_temp::<bool>(egui::Id::new("wm-graphic"))).unwrap_or(false);
@@ -681,6 +783,10 @@ pub fn show(app: &mut LightcraftApp, ctx: &egui::Context) {
                             ui.checkbox(&mut wm.shadow, crate::i18n::tr("Shadow"));
                         }
                     }
+                    if opts.watermark != wm_shown {
+                        // the preview above was drawn with the old settings
+                        ui.ctx().request_repaint();
+                    }
                     }
                     ui.add_space(4.0);
                     if opts.format == F::Tiff {
diff --git a/docs/parity-checklist.md b/docs/parity-checklist.md
index 099411089..569aca39d 100644
--- a/docs/parity-checklist.md
+++ b/docs/parity-checklist.md
@@ -391,7 +391,7 @@ differences and missing bindings are in [ui-parity.md](ui-parity.md#shortcuts).
 | LR-EXP-HDR | HDR output | P2 | 🟡 | `cmd:app.export`, `crates/ui-egui/src/panels/dialogs.rs` | HDR output checkbox in the export dialog: gain map JPEG, PQ AVIF, float TIFF; no HDR presets yet |
 | LR-EXP-SHARPEN | Output sharpening | P1 | ✅ | `cmd:app.export` (`sharpen`, `sharpenAmount`) | |
 | LR-EXP-METADATA | Metadata policy | P1 | ✅ | `cmd:app.export` (`metadata`, `removeLocation`) | |
-| LR-EXP-WATERMARK | Watermark | P1 | ✅ | `cmd:app.export` (`watermark`: text, or `{text, vertical, size, opacity, anchor, inset, color, shadow, image, imageWidth}`), `crates/engine/src/export.rs` (`Watermark`, `WATERMARK_PARAMS`) | text (`size` = height as a fraction of the short edge, 0.005..0.5, default 0.035; `color` sRGB `[r,g,b]`; `shadow`; Japanese vertical glyph forms and origins, tested by `biz_ud_vertical_watermarks_place_punctuation_at_the_top_right`; extended grapheme cells keep decomposed dakuten/handakuten and Latin accents together, tested by `vertical_watermarks_keep_combining_marks_in_one_cell` and `upright_watermark_cell_retains_multiple_glyphs` (see `docs/vertical-watermarks.md`)) or a graphic with transparency (`image` path, `imageWidth` = fraction of the photo's width, 0.01..1, converted to the output colour space); `anchor`, `inset` (fraction of the short edge, 0..0.4), `opacity` 0..1. Unknown keys and out-of-range values are errors (issue #183) |
+| LR-EXP-WATERMARK | Watermark | P1 | ✅ | `cmd:app.export` (`watermark`: text, or `{text, vertical, size, opacity, anchor, inset, color, shadow, image, imageWidth}`), `crates/engine/src/export.rs` (`Watermark`, `WATERMARK_PARAMS`) | text (`size` = height as a fraction of the short edge, 0.005..0.5, default 0.035; `color` sRGB `[r,g,b]`; `shadow`; Japanese vertical glyph forms and origins, tested by `biz_ud_vertical_watermarks_place_punctuation_at_the_top_right`; extended grapheme cells keep decomposed dakuten/handakuten and Latin accents together, tested by `vertical_watermarks_keep_combining_marks_in_one_cell` and `upright_watermark_cell_retains_multiple_glyphs` (see `docs/vertical-watermarks.md`)) or a graphic with transparency (`image` path, `imageWidth` = fraction of the photo's width, 0.01..1, converted to the output colour space); `anchor`, `inset` (fraction of the short edge, 0..0.4), `opacity` 0..1. Unknown keys and out-of-range values are errors (issue #183). The Export dialog previews it on the first exported photo's thumbnail (`draw_watermark_preview` scales the 6 px minimum text size to the preview so it matches the file), tested by `watermark_preview_scales_the_minimum_text_size` and `export_dialog_previews_the_watermark` |
 | LR-EXP-NAMING | File naming | P1 | ✅ | `cmd:app.export` (`naming`, `startNumber`), `crates/engine/src/rename.rs` (`expand_tokens`) | one template language for export, Rename Photos and import renaming: `{name}`, `{num}` (number at the end of the name), `{seq}` / `{seq:N}`, `{date}` / `{date:%Y-%m-%d}`, `{folder}`, `{camera}`, `{lens}`, `{iso}`, `{rating}`, `{title}`, `{creator}`, `{ext}`; free-form template rather than a list of named schemes |
 | LR-EXP-LOCATION | Destination folder | P0 | ✅ | `cmd:app.export` (`dir`, `subfolder`, `conflict`: unique / overwrite / skip), `cmd:export.checkTarget`, `crates/ui-egui/src/panels/dialogs.rs` (Choose… folder picker), `crates/engine/src/originals.rs`, `crates/catalog/src/safe_file.rs` | folder picker on the desktop; existing files get `-2`, `-3`… by default; the policy covers a file and its sidecars together; a catalogued original (or its sidecar) is never written over, whatever the policy or an exact `path` (export, `ui.render`, MCP `render_photo`, merge `previewPath`, `lightcraft-cli render`); files are written to a temp file and renamed into place (issue #93; not synced file by file — exports can be made again, issue #134) |
 | LR-EXP-PREVIOUS | Export with previous settings | P0 | ✅ | `cmd:app.exportPrevious`, `cmd:dialog.export` | last options persist in prefs.json; dialog prefilled; no named export presets yet |