I put some links in the comments below. But most of the ‘information’ I have is from news and documentaries about Xu Xiaodong. You can check the wikpeida article, but it’s just wikpedia.

I also know of someone who went to tibet as a tourist through Nepal. Their phone had to be surrendered for thorough checking, they apparently painstakingly checked all images. I don’t expect anybody to believe this as I can’t provide proof that it did happen.