diff --git a/crates/create/src/extract.rs b/crates/create/src/extract.rs
index 2b3a0ffd73..b5500f60c3 100644
--- a/crates/create/src/extract.rs
+++ b/crates/create/src/extract.rs
@@ -236,12 +236,16 @@ fn image(doc: &Document, s: &Stream) -> Result<(&'static str, Vec<u8>), String>
     let mut alpha = if mask { None } else { soft_mask(doc, s, w, h).or_else(|| stencil_mask(doc, s, w, h)) };
     let key = if mask { None } else { colour_key(doc, s) };
     // Keep the existing JPEG and stencil-mask Decode handling separate from lossless colour images.
-    let endpoint = |value: Option<&Object>| value.map(|v| doc.resolve(v)).and_then(|v| v.as_f64());
+    let endpoint = |value: Option<&Object>| value.map(|v| doc.resolve(v)).and_then(|v| v.as_f64()).filter(|v| v.is_finite());
     let inverted = (jpeg || mask)
         && s.dict
             .get(b"Decode")
             .map(|d| doc.resolve(d))
-            .and_then(|d| d.as_array().map(|a| endpoint(a.first()) > endpoint(a.get(1))))
+            // Both ends have to be finite numbers, as for lossless images, or the default mapping stands.
+            .and_then(|d| {
+                let a = d.as_array()?;
+                Some(endpoint(a.first())? > endpoint(a.get(1))?)
+            })
             .unwrap_or(false);
     // In a PDF a CMYK JPEG's samples are ink amounts unless /Decode inverts them, while image
     // viewers read a CMYK JPEG file as inverted (Adobe's convention): as is, it would show as
diff --git a/crates/create/src/tests.rs b/crates/create/src/tests.rs
index 4a1e007fd4..ff871d53ae 100644
--- a/crates/create/src/tests.rs
+++ b/crates/create/src/tests.rs
@@ -2237,12 +2237,14 @@ fn a_stencil_masks_decode_array_can_hold_references() {
     for decode in ["[0 5 0 R]", "[6 0 R 1]", "[6 0 R 5 0 R]"] {
         assert_eq!(export(decode), identity, "{decode}");
     }
-    // A reference that only leads back to itself holds no number. The read ends, and the file comes
-    // out one way round or the other.
-    for decode in ["[7 0 R 0]", "[1 7 0 R]", "[8 0 R 0]", "[1 8 0 R]", "[7 0 R 8 0 R]"] {
-        let file = export(decode);
-        assert!(file == inverted || file == identity, "{decode}");
+    // A reference that only leads back to itself holds no number, and an end that is missing or isn't
+    // a number leaves the default mapping, whichever end it is.
+    for decode in ["[7 0 R 0]", "[1 7 0 R]", "[8 0 R 0]", "[1 8 0 R]", "[7 0 R 8 0 R]", "[1]", "[1 /Name]", "[/Name 0]"] {
+        assert_eq!(export(decode), identity, "{decode}");
     }
+    // Equal ends aren't the two ways round either, and a number too long to hold reads as infinite.
+    assert_eq!(export("[1 1]"), identity);
+    assert_eq!(export(&format!("[{} 0]", "9".repeat(400))), identity);
 }
 
 /// A mask of other proportions than its image is scaled to it, however far apart they are: the