This set of 5 clipping mask pairs (10 masks total) is great for adding interest to the background of a picture. Clip (alt+ctrl+g in CS+, ctrl+g in PSE) your photo to the top or first layer, then clip a different photo, paper, or even the same photo at a different size to the background mask. Play with opacity levels and layer blending modes for even more fun and flexibility! The masks are much larger than what's shown on the preview (largest one is 2708x2042 px).

[Note: contains 5 .psd files, and 10 .png files for if you can't read the .psd ones.]