Click on template designer
Then you are going to click on "background"
Then you are going to click on the background image box. There's a little arrow, it will open the box below.....
Click on upload image, and a box will pop up, choose "upload"
After you upload your photo and you are sure you want it, click "apply to blog" in the upper right hand corner.
And that is how you use a photo for a background. With this way, you can use anything for a photo. Have a logo? Personal blog and want a photo of your kids? etc.
FREE BLOG BACKGROUNDS: