In 2010 Topps made had what they called their Million Card Giveaway. As part of the program they needed pictures of all of their cards from 1952 - 2010. The pictures included the front and back of every baseball card.
I was able to figure out the system they used for the URL of each card. With that, I could get a scan of any card. It was a tremendous resource.
A few weeks ago I tried to get the scan of a card for a post I was writing. I filled in the URL, hit enter, and got this:
It looks like the pictures are gone. I tried a few other random card number from different years and got the same message.