It’s far simpler than you’d imagine! If you’re willing to pay a small amount, you can try CanStockPhoto. The smallest photos are $3, and that’s really all you’d need. Make sure to save the receipt and screenshot the download page to prove that you bought it. CanStockPhoto is the one we at Liliom use, simply because we have the receipt showing that we’ve purchased the item free and clear.
If you’re loathe to spend even $3 on something so small, there are still tricks to the trade! Take your own photos, find a friend or two, or an awesome scenic view. Cite yourself as the photographer, get your friends to sign a sample release form, and that’s that.
Don’t have friends or living spaces that are photogenic? Try Pixabay! As before, be sure to screenshot the page for the photo you downloaded. Licensing rights can change over the years, and you want to be able to prove that when you downloaded the image, it was free to use.
Do be sure to research the images though, especially on the free sites. Run a Google Image Search and make sure that the picture posted wasn’t actually stolen from someone else who didn’t release it to the public domain. If you only find it on other free sites or on wallpaper sites, then you officially have a teaser background to play with. Enjoy!