I've just setup a site which provides free background images for use on web pages. Being new, I only have a few images which I have produced so far and would like to bulk out my stock a little.

So, does anyone know where a could get a good selection of background images (preferably tileing ones) which I could put up on my site for download?

Obviously, I don't want to go around stealing other peoples work, so please don't just suggest that I grab good looking ones from wherever I find them. I am more looking for a bundled selection which I could pick up for as small a cost as possible, but which I would also have the rights to distribute. I do not mind if they are not unique as I am also filling my stock with my own creations, but it will take time for me to produce a good number of quality items.