Ignoring the outcome of the case which ended with Fairey being convicted with nothing to do with the ethics of the Hope Poster, I do believe that Fairey transformed the picture enough to create a wholly new piece. Not crediting or asking the original photographers for permission is a sleazy thing to do however.
Up until recently, I really never credited another person’s creative work. From my point of view, very few people were going to see it anyways, so why go through the trouble. However, as I began to upload these works onto the web, where the expectation is that many people will see it, I did ask for permission for works from artists that, and here’s the kicker, specified “no reposti”. Otherwise in the circle I was in, if not explicitly specified, it was free game. And if the artists disapproved or the work was licensed, the work was swiftly taken down. Official content was a more murky territory. It’s funny in a way, the moment official works become published, some groups jump on it immediately if they are interested. But the moment it gets officially licensed for an English version, the same people back off immediately.
If you know, you know.