Andrew Ferguson has posted up a great post on where to find Great Free Photos for Your Blog
Knowing where to look is just as important as what you find. I know most people’s first instinct is “Google Images!” Ignore that instinct. Google Images is useful for some things, but not really for this. There’s too much of a legal quagmire regarding usage rights and let’s be honest, the photos you find are pretty lame.
I know my posts would benefit from more images (or any images!). Good advice to follow.