I, too, am depressed by this.
Besides, Ken, what you're asking us to do here is, for lack of a better word: IMPOSSIBLE.
Due to the expanse of the internet, one image could make it to several different places.
On top of that, a lot of the images, especially the random anime ones you find on photobucket and/or Yahoo search, don't have a name or author one can refer to. So even if you wanted to give credit to the creator of said image......Who would you credit it to?
And lastly, most artists that do post their works on the internet allow others to use said image/video/song/whatever, and they will let people know if they want to be credited for the image.