Rasputin - 4:58 pm on Sep 5, 2011 (gmt 0)
Use of images is quite a minefield for SEO.
I use some wikipedia images, always credited to the original picture even when GNU, but I'm reducing them as part of our 'post-panda improvements' because I suspect they could be used as a clue by google that a site has been created using wiki information rather than having original content.
There are several sites which have loads of great photos at low prices so I'm using them for replacements when possible and I can't take the photo myself.
That said, it is often suggested that there is a case for linking to authority sites as a way of improving a sites SEO, so it is possible that removing the links to wikipedia is a bad thing.
That is without even starting on the issue of whether having images is a good thing because it enhances user experience - or a bad thing because it slows down pageload time (I have a travel site and choose to use lots of images despite the slower page load times, but I'm pretty sure it counts against me - but hopefully the pages attract more links because of it)
As aristotle says, the most common and most successful option often seems to be just to steal pictures without giving credit, and I haven't seen any evidence at all that sites stealing our own images are penalised in any way. I'm not recommending it though!
Overall it's a tough call, I'll be interested to hear other thoughts