I just thought I would pass this along in case anyone else runs into this problem. I don't think this is a bug with the Image Gallery module but just a unfortunate set of circumstances.
I had the Image Gallery module up and running on a clients site an then I got a email from the client stating that their gallery page had stopped showing photos. After investigating it turns out that they had commented out their Google Analytics code. This code is located right before the closing body tag. The Image Gallery module inserts its script tag code in the same location. It turns out that if there's a commented out script tag block in this location the Image Gallery initialization script tag code will get inserted into the this commented out block. Thus, none of the gallery photos will be shown (actually they are there but just hidden and don't get displayed until the init script is run).