The Internet Pinball Database is a tremendous resource. I have not yet looked for a pinball and found that they did not have any photos of it. There are also ratings of the machines and links to download roms and pinball manuals.
I had never heard anything about the creation of the IPDB or how it continues to operate until I came across this interview with one of the men behind the site.
RVA Pinball 
It was a great interview to give – and I think a lot of people don’t realize the depth of the pinball hobby, the history behind it, or the amount of knowledge and craftsmanship fans have.