Well, all of the image files I want to add are PNG files.
I can use the images by manually loading them into PEP3 for each widget.
So that shouldn't be an issue.

Also, as I said, just unzipping and re-zipping the GEF gallery file makes PEP3 throw this error.
Are there any specific constraints to the ZIP format that I'm not aware of?
I tried 7-zip (to create a .zip file, not a .7z obviously) as well as the builtin zip support from Win 7 (select folders, right click, send to, compress....).

Sebastian