What app can I use to overlay or hide a picture under another one?

If you're looking to put one picture on top of another, you might be thinking of compositing or layering. There are several apps available for this—like Photoshop or GIMP—that let you easily overlay images. Just make sure to play around with the layer settings to get the look you want!

Have you heard of steganography? It's more about hiding information within images, but if that's what you're after, there are apps that specialize in that too. Steganography is a way to conceal a picture within another, so it may be worth exploring if you want to hide something creatively.

Just so you know, there are different ways to interpret hiding a picture under another. Besides simple layering, you can also try using apps that allow for project files where layers can be adjusted later. This way, the hidden picture can be revealed as needed. Check out some photo editing tutorials online for more tips!