I think the question that begs to be asked is: what kind of blog is it and what type of pictures are you anticipating you'd want to be using?

If it's a site about where you went on your vacation, and the pics you took turned out like shit, or you need plates of food to illustrate a site on cooking - you might consider getting something like Hemera's "The Big Box of Art", or a similiar product, that has thousands of images, clipart, etc that are royalty free to use on web pages, in print publications, etc.

You can usually find several products like that at a computer center that carries a good selection of software. Or even check www.microcenter.com and order one online.

You could also use a stock photography site like Fotolio ... can get pics for a $1.