Magazine, newspaper pictures etc can also be good sources of inspiration. Incidentally to avoid any copyright issues, I only use my own pictures on my websites but of course that doesn't stop me being inspired by other images I've seen. It's the writing that is inspired by what I've seen that makes it on to my websites, blogs, Chandler's Ford Today posts and so on.
Landscapes are the best inspiration for me. The picture at the top of this was taken in the Scottish Highlands on one of my holidays and just looking at it I can sense the wildness, the freedom, the sheer space there. (And remember how cold it was on top of that hill too!). But that wildness and space has helped me flesh out my fictional world. Sometimes it can inspire opposite reactions. My Fairy Kingdom has areas made barren by too much magic going through it during historic magical wars. Looking at the above picture, I see these barren areas as the direct opposite of the image.
So how can you use pictures to inspire your writing?