Justin Cormack wrote:
For everything other than self-created pictures, yes. If the uploader cant produce documentation, delete the image.
I'd say claimed self-made images are often the worst cases. If you can't find a source online, what can you do but trust the uploader? Or, even if you do find an online source, how do you know that the uploaded _isn't_ the creator if the other site doesn't document _its_ sources in sufficient detail?
Okay, you can choose _not_ to trust the uploader and instead nominate the image at IFD. But that's hardly assuming good faith.
For a specific recent example, see [[Image:JP4.jpg]] on enwiki. Or, for that matter, [[Image:Teabagging.jpg]] and the ensuing IFD debate at http://en.wikipedia.org/wiki/Wikipedia:Images_and_media_for_deletion/2006_Ja...