The theory is that a buggy photo has been added, making the gallery viewer to crash. If you know which photo, have the owner remove it from the group.
Buggy photo means a photo which is not a .JPG file being uploaded to Panoramio, which again renames all files to .JPG. The photo viewer expects a normal .JPG file but gets a .JPG file with the wrong content. It's like opening a bag of candy, just to discover that It's filled with glass marbles... Send an email to the team if you can't solve this yourself: questions[at]
panoramio.com