Others have already noted and praised the volunteer-led website Findagrave. I've found some of Michael's ancestors on this site from places in Oklahoma and Kansas. A while ago I wanted to add my own ancestors for whom I had gravestone digital photos [some of those photos were real photos that were scanned]. However, there were strict rules for uploading such photos and I couldn't be bothered. Actually the truth was I didn't know how to adjust pixel length and the corresponding file size of a digital photo. Despite the fact I work on a mac, I haven't an artistic bone in my body, so I've never used the mac for its artistic superiority.
I had Arcsoft's Photo Studio 4 already on the computer, so I took some to figure things out. I'm glad to say that I've now uploaded all my photos and created very information-rich memorials for all my close-in ancestors [grandparents, great-grandparents, and double-greats]. I have 26 memorials and 36 photos uploaded. Not bad.
But no web site is perfect. Findagrave is NOT a wiki. That is, once a memorial is set up (i.e. an entry in their database), no one but the creator can edit that memorial. Because Findagrave has been operating for a while, there is the chance, as in my case, that some of your close in relatives have been entered already. Someone entered my great-grandparents for some odd reason. She was not doing the entire cemetery. Perhaps she liked the stone (it is large). However, I know this couple has only 12 living descendants of which I am one. So, I can't do the connections I would like because she "owns" the memorial. I can only email her and hope she changes what is incorrect or adds what is lacking.
All in all, someday this will be quite the boon for genealogy.
[Added note: The very wonderful lady responded quickly to my email request and changed what I asked! She even volunteered to transfer ownership of my great-grandparents' memorial to me. Cool people on Findagrave.]