There are several good webpages with photos, but you would want to contact the owners and get permission, and provide credentials, before posting them at your store. Not sure about pics from magazines and such...I know several people here work in LFS--maybe they can offer better advice.
See if you can get your store to buy a digital camera--then you can take pics of the animals/plants as they come in, and print them off, with specs. Would take a bit, but eventually you'd likely have something on all the ones you guys carry.