Square thumbnails aren't being built

Hi,

I use Gallery2 for my photo album. Everything was going great until my website and database went down for awhile...no idea why...and then when it came back up, I no longer can build thumbnails when I add photos. The photos upload fine, but the thumbnails don't get built.

I deactivated the "square thumbnail" option in site admin but it didn't help. And I don't know how to put the gallery in debug mode...sorry...I don't know much about the tech side of things...

I did try to rebuild the thumbnails in the whole album but it didn't help either. I prefer not to have to rebuild all the thumbnails in my photo album every time I add a photo...because I already have 83,000 photos in my album.

Are there any other simple things I can try? Otherwise, it looks like I will have to hire someone...

thank you so much for your help,
manderly