Today I wanted to make a Colonial flag waving in the breeze. However, I could only find a flat flag (see below).
I figured out how to give it a "waving in the breeze" look using the Filter command in Photoshop. Use a really large brush: choose a round, solid brush, then hit the ] key until it is plenty big. If it's too big, hit the [ key to reduce the size. Now open the Filter tab, then the Liquify tab. Choose the top icon, the Forward Warp tool. Starting with the edges of the flag, just nudge the edges until they look right. The result is a waving flag (see bottom image).
I added a flag pole and put in a sky blue background. Pretty cool hey?