@bradvin. – Hi There. I come across the same error message as others:
Thumbnail Generation Alert!
There is a problem generating thumbnails for your gallery. Please check that your hosting provider has the GD Image Library extension installed and enabled.
I checked my host, but GD image library is installed and enabled.
I deactivated all plugins but FOOGallery and FOOBox, but the issue remains.
Running the testing gives the fore mentioned Error.
Is there an update to this situation?