Does Gallery Plugin use GD Library when Imagemagick is not installed?

I have a website on a 1&1 Linux Server where Imagemagick is not installed. I would have to install it manually, but wanted to see if Gallery worked anyway. Sure enough it works, but there are some weird issues. One is that sometimes it does not process thumbnails in the manager. I have a gallery with 16 items and 2 of them cannot be process for some reason. Then sometimes when I try to just upload one image, I get an error during the upload "Please specify a file to upload" which is strange.

I am running MODX 2.2.4 with Gallery 1.5.2. Environment is
PHP 5.2.17, mySQL 5.1.49, unfortunately it is a shared environment so I can't turn off magic_quotes_gpc.

Any ideas?