Comment 9 for bug 427100

Some observations which may help:

1) All of the library "textures" have an alpha channel, but only a few cause this crash.

2) Irfanview (Windoews) flags the files which cause crashes as "improper channel number 5", but does not crash.

3) Once the crash occurs then all thumbnails including the desktop thumbnails do not display. (This is consistent with a library problem).