Quick summary

Some photos look corrupted or are too small to edit. Imagen doesn't upload photos whose short side is under 300 pixels. These are usually thumbnails or damaged files.

How to fix this

1. Check the size of the photos that fail. If they're tiny, they're probably previews or thumbnails, not the full photos. Copy the full-size originals from your camera card or backup.
2. Photos saved from social media, messaging apps or web galleries are often shrunk. Use the original camera files.
3. Open each photo in another viewer. If it won't open or looks broken, it's damaged. Replace it.
4. Remove the photos you can't replace, and create the project again.