Triple signed photograph of the 3 Stooges Larry, Curly and Moe not in great condition, flat signed in black ink

as u can see, it is not in great condition, some of it I believe could be cleaned up, but I do not attempt this as I do not know how to go about using photo cleaner and don't want to further damage this. My grandpa wrote on the back of the photo "old friends" Photo is of the stooges sitting on a cannon, each of them holding a cannon ball, I could not tell you what movie or short this was from. I need to know how to go about getting it authenticated, how much that would cost, as I'm broke, is it necessary? and what would be the best way to sell it? I'm wary of Ebay since they charge and take a percentage, is it worth anything at all? From my searches, it's rare because of all the signatures from each of them, and they are double signed, but the photograph with the creases and small tear is just not in good condition, I've taken good care of it since I found it in the box, but sadly it is what it is. Please help! Thank you very much