If you are using a theme such as Prose, P2, or Twenty Ten, you can change the background image of your website by going to the Appearance > Background menu. There, you will be able to upload a background image of your choice. For optimal website performance, we recommend that you only use an image with a small file size.
For sample background images, please see the Sample Background Images to Tile and Sample Background Images to Tile Horizontally pages.
If you do not select “Tile” for the “Repeat” value, the background color you select will fill in wherever the background image is not used. For example, if you have a 50×100 pixel image that is set to “Tile Horizontally,” the top 100 pixels of your website background will consist of the repeated background image, while the rest of the website background below 100 pixels will only show the background color.