BillionGraves would like you to upload cemetery images to their site. I suppose they would like me to upload images as well. I'm not, but it's just a personal preference.
Before you share tombstone images with BillionGraves, take a look at their terms of service, which (last time I checked) was not linked to from their home page. I had to do a Google search to find it. I've taken a look at the terms of service for the site and have chosen not to participate.
Know what the "deal is" before becoming a part of anything. It's ok to give things away as long as you are aware of what you are giving up.
If the terms of use for BillionGraves aren't clear to you, see what the Legal Genealogist had to say about them. BillionGraves can do what they want with the pictures you submit and you can't say a thing about it. Period. Because it was in the terms of use. It is the user's responsibility to read the terms of use before participating.
I'm not saying you should participate or not participate. That's your decision, not mine. Just be informed before you make decision. If how they may use your pictures doesn't bother you, that's ok. I just don't like people being surprised.
And don't get all frustrated if they eventually sell your pictures as part of something.
It was in the fine print.
Just like that foreclosure clause on a mortgage.