Hi,
I’ve been running into this issue a couple of times lately, and generally it seems to happen when images have strange dimensions, for example being really wide, but very short. You can see what I’m talking about here, as at first I thought it was an issue with Matrix:
http://help.pixelandtonic.com/brandonkelly/topics/certain_images_break_matrix_column_width
I was wondering if this is a known bug that is being worked on as I can’t find anything on the Bug Tracker (mainly because any search I do gets ‘invalid action’)? If so it would be good to get a status update on this as it’s proving very frustrating for a couple of my clients when they go to edit content.
Cheers