In case you are not aware, if you have photos on flickr, and the license of your image(s) is set to anything other than "all rights reserved," flickr is selling those photos as wall art. So, if you don't want them to be selling your photos and making money off of your work without your express permission and without you seeing a penny of it, you need to make sure all of your photos are set to have the "all rights reserved" license. I believe that is the default setting, but just to be sure, you may want to go into the settings in your account and run a batch license update for all images. Flickr's gall is flabbergasting to me.
BTW when I found out about this today, I went to some of my photos and there was a "wall art" option there, and I freaked out. But then I realized I was logged in, so I decided to log out of the site and then view it. The wall art option was gone, so now I know my photos are safe.
edit- regarding my last sentence..I should clarify "safe from flickr selling them without my express permission" ..but not safe from illegal use and theft of anyone on the web that feels like stealing them and using them for their any desire.