Comment 8 for bug 255030

gnome imaging apps follow the freedesktop.org thumbnailing spec:
http://people.freedesktop.org/~vuntz/thumbnail-spec-cache/

There is no gnome-wide disable-thumbnail setting, and I doubt you'll convince anyone that it is worth having one. (Part of the probably is that nautilus, gthumb, and eog can be present on a system in any combination.) gnome generally tries to minimize the number of user settings. That's controversial, and kde takes a different approach, but it is the general gnome approach.

gThumb has a disable-thumbnail setting, although it can only be enabled through gconf-editor. Maybe you can convince eog to do the same, but such a patch would have to go upstream.

However: have you tried "chmod -R 550 ~/.thumbnails"? Making ~/.thumbnails read-only would probably resolve your issue. (If it doesn't, that would be a serious bug.)

- Mike