diff --git a/src/calibre/utils/podofo/images.cpp b/src/calibre/utils/podofo/images.cpp
index dc9cf32bd9..6e9b6029f9 100644
--- a/src/calibre/utils/podofo/images.cpp
+++ b/src/calibre/utils/podofo/images.cpp
@@ -78,7 +78,7 @@ dedup_images(PDFDoc *self, PyObject *args) {
             const PdfReference &canonical_ref = x.first.reference();
             for (auto &ref : x.second) {
                 if (ref != canonical_ref) {
-                    ref_map[ref] = x.first.reference();
+                    ref_map[ref] = canonical_ref;
                     objects.RemoveObject(ref).reset();
                     count++;
                 }