Where photos should be, there are red Xs. Or blank boxes. Or just empty whitespace where you remember the chart was. The text is fine but the visuals are gone.
What's actually going wrong
Embedded image format unsupported. The image uses a compression scheme your viewer doesn't recognise (JBIG2, JPEG2000 in older viewers). Embedded data corrupted. The image data exists but is partially garbled. External image reference. The PDF references an image file elsewhere that's missing.
Real PDFs almost always embed images. If yours has external references, that's an unusual export problem.
The quick fix
Compress the PDF in Flint. The compressor re-encodes images into universally-supported formats. Images that wouldn't render in your viewer typically come back.
If compression doesn't help, convert to JPG — this renders each page including images to a flat image, capturing whatever's visible. Then convert back to PDF for a fresh file where images are visible.
If that didn't work
If images are genuinely missing (not in the file at all), source recovery is needed. Re-export from the source document or get a fresh copy from the sender.
For PDFs where images use external references, the references can't be repaired. Get source and rebuild.
Prevent it next time
Embed images at export. Avoid unusual image compression schemes if compatibility matters. Test PDFs on multiple viewers before distributing.
FAQ
Why do images show as red Xs in my PDF?
The viewer recognises that an image should be there but can't render it — broken data or unsupported format. Compress in Flint to re-encode.
Can I extract whatever images are visible?
Yes. Convert PDF to JPG renders each page including any visible images. You get one image per page; crop to extract specific photos.
Why are images missing from one PDF but not another?
Specific to that file's image embedding. Different exporters produce different image structures. Some viewers handle them all; some don't.
Will compression make images higher quality?
No — compression can't add information that's not there. But it can re-encode partially-broken images into clean equivalents that render where the original didn't.
Images that won't render usually come back with Flint's compressor. Re-encode and re-display.