diff --git a/crates/pptx/src/read.rs b/crates/pptx/src/read.rs
index 886201a30..189bd81de 100644
--- a/crates/pptx/src/read.rs
+++ b/crates/pptx/src/read.rs
@@ -24,11 +24,24 @@ use crate::PptxError;
 use crate::opc::{self, Package, Rels};
 use crate::xml::{Doc, El, Node};
 
+/// A snapshot of the import state a discarded read rolls back to.
+pub struct Mark {
+    diagram_xml_bytes: usize,
+    media: usize,
+    media_keys: usize,
+    tag_bytes: usize,
+    tags_capped: bool,
+    kept_sidecar_bytes: usize,
+    kept_chart_keys: usize,
+}
+
 /// Import state shared by all parts.
 pub struct Imp<'a> {
     pub pkg: &'a Package,
     pub media: Vec<MediaItem>,
     pub media_by_part: HashMap<String, MediaId>,
+    /// Keys added to `media_by_part`, in order, so a rollback removes only its own.
+    pub media_keys: Vec<String>,
     pub next: u32,
     pub slide_by_part: HashMap<String, SlideId>,
     pub custom_show_names: HashMap<String, String>,
@@ -40,6 +53,8 @@ pub struct Imp<'a> {
     pub kept_sidecar_bytes: usize,
     /// Cached kept sidecars by normalized chart part name.
     pub kept_charts: HashMap<String, deckcraft_model::chart::ChartKept>,
+    /// Keys added to `kept_charts`, in order, for rollback.
+    pub kept_chart_keys: Vec<String>,
     /// Add-in tags parts, parsed once each, by normalized part name.
     pub tags_by_part: HashMap<String, Arc<[(String, String)]>>,
     /// Bytes of tags copied into the model so far (see [`MAX_TAG_BYTES`]).
@@ -73,16 +88,36 @@ impl Imp<'_> {
         let content_type = self.pkg.content_type(part).filter(|c| !c.is_empty()).unwrap_or_else(|| crate::mime_for(&name).to_string());
         let id = MediaId(self.alloc());
         self.media.push(MediaItem { id, name, content_type, data: Arc::new(data), link: None });
+        self.media_keys.push(key.clone());
         self.media_by_part.insert(key, id);
         Some(id)
     }
-    /// Drop the media copied since the list was `len` long, with their part-cache entries: used when
-    /// the content that read them is discarded, so they are neither kept nor reused uncharged.
-    pub fn forget_media_from(&mut self, len: usize) {
-        if self.media.len() > len {
-            let gone: std::collections::HashSet<MediaId> = self.media[len..].iter().map(|m| m.id).collect();
-            self.media.truncate(len);
-            self.media_by_part.retain(|_, id| !gone.contains(id));
+    /// What a discarded read must give back: the budgets it charged and the media and kept-chart
+    /// entries it added (see [`Imp::rollback`]).
+    pub fn mark(&self) -> Mark {
+        Mark {
+            diagram_xml_bytes: self.diagram_xml_bytes,
+            media: self.media.len(),
+            media_keys: self.media_keys.len(),
+            tag_bytes: self.tag_bytes,
+            tags_capped: self.tags_capped,
+            kept_sidecar_bytes: self.kept_sidecar_bytes,
+            kept_chart_keys: self.kept_chart_keys.len(),
+        }
+    }
+    /// Undo everything since `m`: only the entries added since are removed, so the cost follows
+    /// what the discarded read added, not the size of the caches.
+    pub fn rollback(&mut self, m: &Mark) {
+        self.diagram_xml_bytes = m.diagram_xml_bytes;
+        self.tag_bytes = m.tag_bytes;
+        self.tags_capped = m.tags_capped;
+        self.kept_sidecar_bytes = m.kept_sidecar_bytes;
+        self.media.truncate(m.media);
+        for k in self.media_keys.drain(m.media_keys..) {
+            self.media_by_part.remove(&k);
+        }
+        for k in self.kept_chart_keys.drain(m.kept_chart_keys..) {
+            self.kept_charts.remove(&k);
         }
     }
     /// Media item for an external link.
@@ -454,6 +489,7 @@ pub fn import_theme(bytes: &[u8]) -> Result<(deckcraft_model::theme::Theme, Vec<
         pkg: &pkg,
         media: vec![],
         media_by_part: HashMap::new(),
+        media_keys: vec![],
         next: 0,
         slide_by_part: HashMap::new(),
         custom_show_names: HashMap::new(),
@@ -461,6 +497,7 @@ pub fn import_theme(bytes: &[u8]) -> Result<(deckcraft_model::theme::Theme, Vec<
         vml_previews: HashMap::new(),
         kept_sidecar_bytes: 0,
         kept_charts: HashMap::new(),
+        kept_chart_keys: vec![],
         tags_by_part: HashMap::new(),
         tag_bytes: 0,
         tags_capped: false,
@@ -499,6 +536,7 @@ pub fn import_checked(bytes: &[u8]) -> Result<(Presentation, Vec<String>), PptxE
         pkg: &pkg,
         media: vec![],
         media_by_part: HashMap::new(),
+        media_keys: vec![],
         next: max_id.max(1),
         slide_by_part: HashMap::new(),
         custom_show_names: HashMap::new(),
@@ -506,6 +544,7 @@ pub fn import_checked(bytes: &[u8]) -> Result<(Presentation, Vec<String>), PptxE
         vml_previews: HashMap::new(),
         kept_sidecar_bytes: 0,
         kept_charts: HashMap::new(),
+        kept_chart_keys: vec![],
         tags_by_part: HashMap::new(),
         tag_bytes: 0,
         tags_capped: false,
diff --git a/crates/pptx/src/read/chart.rs b/crates/pptx/src/read/chart.rs
index 358f88ff5..059b79031 100644
--- a/crates/pptx/src/read/chart.rs
+++ b/crates/pptx/src/read/chart.rs
@@ -485,6 +485,7 @@ pub(crate) fn capture_kept(imp: &mut super::Imp, chart_part: &str) -> deckcraft_
             kept.rels.push(ChartRel { id: r.id, rel_type: r.ty, target: r.target_raw, part: r.target, external: false });
         }
     }
+    imp.kept_chart_keys.push(key.clone());
     imp.kept_charts.insert(key, kept.clone());
     kept
 }
diff --git a/crates/pptx/src/read/shapes.rs b/crates/pptx/src/read/shapes.rs
index 98ec3a155..3002e4e13 100644
--- a/crates/pptx/src/read/shapes.rs
+++ b/crates/pptx/src/read/shapes.rs
@@ -471,33 +471,53 @@ fn frame(imp: &mut Imp, part: &Part, ctx: &mut IdCtx, e: &El, depth: usize) -> S
     };
     // Keep the parts it points to so a save writes it back whole (#203). A part with relationships
     // of its own, or an external link, can't be carried: the save then falls back to the preview.
-    let (xml_before, media_before) = (imp.diagram_xml_bytes, imp.media.len());
-    let parts = super::rel_refs(e)
-        .into_iter()
-        .map(|id| {
-            let rel = part.rels.get(&id).filter(|r| !r.external)?;
-            let pkg = imp.pkg;
-            if *imp.has_rels.entry(crate::opc::norm(&rel.target)).or_insert_with(|| !pkg.rels(&rel.target).items.is_empty()) {
-                return None;
+    // Validate every relationship (and charge the budget) before copying anything, so a fallback
+    // that cannot be kept whole copies no part at all.
+    let mark = imp.mark();
+    let mut planned = Vec::new();
+    let mut spent = imp.diagram_xml_bytes;
+    let mut ok = true;
+    for id in super::rel_refs(e) {
+        let Some(rel) = part.rels.get(&id).filter(|r| !r.external) else {
+            ok = false;
+            break;
+        };
+        let pkg = imp.pkg;
+        if *imp.has_rels.entry(crate::opc::norm(&rel.target)).or_insert_with(|| !pkg.rels(&rel.target).items.is_empty()) {
+            ok = false;
+            break;
+        }
+        // A diagram's definition parts copied here count against the same presentation-wide budget.
+        if rel.kind.starts_with("diagram") && !imp.media_by_part.contains_key(&crate::opc::norm(&rel.target)) {
+            let len = pkg.get(&rel.target).map_or(0, |b| b.len());
+            if len > MAX_DIAGRAM_PART_BYTES || spent.saturating_add(len) > MAX_DIAGRAM_XML_BYTES {
+                ok = false;
+                break;
             }
-            let (kind, target) = (rel.ty.clone(), rel.target.clone());
-            // A diagram's definition parts copied here count against the same presentation-wide budget.
-            if rel.kind.starts_with("diagram") && !imp.media_by_part.contains_key(&crate::opc::norm(&target)) {
-                let len = pkg.get(&target).map_or(0, |b| b.len());
-                if len > MAX_DIAGRAM_PART_BYTES || imp.diagram_xml_bytes.saturating_add(len) > MAX_DIAGRAM_XML_BYTES {
-                    return None;
-                }
-                imp.diagram_xml_bytes += len;
-            }
-            let media = if rel.kind == "diagramData" { diagram_data(imp, &target) } else { imp.media_for(&target) };
-            Some((id, kind, media?))
-        })
-        .collect::<Option<Vec<_>>>();
-    // A fallback that drops its parts does not keep their bytes charged.
-    if parts.is_none() {
-        imp.diagram_xml_bytes = xml_before;
-        imp.forget_media_from(media_before);
+            spent += len;
+        }
+        if pkg.get(&rel.target).is_none() {
+            ok = false;
+            break;
+        }
+        planned.push((id, rel.ty.clone(), rel.target.clone(), rel.kind == "diagramData"));
     }
+    let parts = if ok {
+        imp.diagram_xml_bytes = spent;
+        let copied: Option<Vec<_>> = planned
+            .into_iter()
+            .map(|(id, kind, target, data)| {
+                let media = if data { diagram_data(imp, &target) } else { imp.media_for(&target) };
+                Some((id, kind, media?))
+            })
+            .collect();
+        if copied.is_none() {
+            imp.rollback(&mark);
+        }
+        copied
+    } else {
+        None
+    };
     let parts = parts.unwrap_or_default();
     s.kind = ShapeKind::Opaque { xml: part.keep(e), preview, label, parts };
     s
@@ -569,6 +589,7 @@ fn diagram_data(imp: &mut Imp, target: &str) -> Option<deckcraft_model::MediaId>
         data: std::sync::Arc::new(xml.into_bytes()),
         link: None,
     });
+    imp.media_keys.push(norm_target.clone());
     imp.media_by_part.insert(norm_target, id);
     Some(id)
 }
@@ -602,7 +623,7 @@ fn smartart(imp: &mut Imp, part: &Part, gd: &El, frame: &Shape, depth: usize) ->
     let tree = d.root.child("spTree")?;
     let mut sub = IdCtx { fresh: true, ..Default::default() };
     let before = imp.smartart_shapes;
-    let (xml_before, media_before) = (imp.diagram_xml_bytes, imp.media.len());
+    let mark = imp.mark();
     let children = sp_tree(imp, &dpart, &mut sub, tree, depth + 1);
     if children.is_empty() {
         return None;
@@ -612,8 +633,7 @@ fn smartart(imp: &mut Imp, part: &Part, gd: &El, frame: &Shape, depth: usize) ->
     if total > MAX_SMARTART_SHAPES {
         // Over the presentation's remaining budget: a placeholder, and nothing charged, nested SmartArt included.
         imp.smartart_shapes = before;
-        imp.diagram_xml_bytes = xml_before;
-        imp.forget_media_from(media_before);
+        imp.rollback(&mark);
         return None;
     }
     imp.smartart_shapes = total;