Learning from a textbook about psychology is not the same as having discussions, generating ideas, learning from others and teaching others. Just my opinion though :).
Despite negativity of this idea.
I think you should totally go for it! How do we know how useful it will be until it's done? There's no point speculating.
What harm can come out of this?
You could simply have all photo's uploaded and allow users to click and select things they feel might be suspicious with comments added. If items are highlighted by many users, it would show that it might be suspicious and it's worth the police looking at! That way they could order the most important and possible remove ones that they have personally looked over and think there are no problems.