I think that approach is akin to the honor system and based on my experiences on the internet I fear that it won't scale well. For some types of images, just be

I think that approach is akin to the honor system and based on my experiences on the internet I fear that it won't scale well. For some types of images, just because the uploader is ok with the file being shared doesn't mean it's a good idea to redistribute it. For a bland example, think of a photo where the uploader doesn't have copyright. I'm sure you can imagine what would happen if someone on the seedier parts of the internet says "hey, if you upload your images to this website, Google will host it for free forever!"