Why not start a forum with photo's that you don't know what's wrong with it, but you know something is wrong. Then people can help out and tell what they did and how they did it.
I personally don't mind at all that people will work in my photo's to make them better. It's till my picture and if I don't like what they do with it, I just ingore it. However those who done big improvements on a photo I've taken, I've learnt a lot from.
I myself would not hesitate to fix someone's photo if i see there's potential in the image, that's not taking advantage of... 1. because the person is a beginner with Photoshop (I'm not, and can give good advice) or 2. because the person imply they aren't happy with the picture and want input, or 3. others can learn a new technique, even if the poster doesn't appreciate it (or didn't ask for it). 4. I learn something new myself while I'm doing it.
If I post an image and people are offended and ask me to remove it from my server, fine. That's not a problem at all. But I do believe sometimes people are too sensitive and might not want to learn stuff and get offended when someone wants to have a go at your photo. If people want to have a go at one of my photo's I take it as people think it has potential to be better, so teach me something new and next time I'll post a better version of another subject with the new technique I was taught.