Isn't it more fun when you're put photo on your blog posts, right? at least it'll looks more colorful than you're not at all, because people like photos. However there's so many ways to finding photos for your blog, at least if you want to do it legaly. Anyway, I have Google searched accrosing the internet and found lots of sites to get pictures. Here are couple of free photo sites
It is almost everybody knows about this site with their main purpose as photo management and sharing application. A good place for searching a quality pictures, most all of them are free legally. But you need to check author’s license at least, before using them for safety.
The site that until now this writing they have more than 8 millions stock photos. These come from many sources and are license-specific. You can view a photo's license by clicking on the license icon, below and left of photos. Membership is free and allows you to rate, tag, collect and comment on photos