I did some investigating and found that they really aren't missing at all. All of the images from Wikia came over during the migration. What is "missing" is the redirects from old image names to the new ones. Basically there are 700 images which were at some point renamed to something more correct. Many wiki pages were then pointing to the old name which was a redirect.
I'm not exactly certain on what should be done. The names were changed for a reason, and it seems silly to create 700 bad redirects just to fix the images. In the end we will need to point to the updated image names. However, this requires some research to find the new name of the image and then fix the bad reference.
Anyone have any better ideas? If you look up the bad image names on Wikia you can find what they are pointing to, and those files exist on the new wiki.
Edited by FlyingRagnar, 04 February 2011 - 10:14 PM.