The reason they load so slow is that they're actual 2000 X 2000 (or something like that) scaled to 50x50 by the website, so you have to load the full-size picture. If you made a copy of the image and scaled it to 50x50 in photoshop and then used that as a link to the full size image, it would load a lot faster.

I made the same mistake about a month ago when I was helping with a website (not really my area either).

The images look nice though!