You may think that creating an animation is a complicated process, but it's really not. In Photoshop, all it means is that you're creating a slideshow that plays automatically. You can control which images the program uses, the amount of time it displays each one, whether it loops the slideshow (automatically starts over), and so on. This kind of control is really handy when you're making website ads. For example, if you're designing a 140-pixel x 140-pixel ad for your costume shop, you need to include a logo, a few costume samples, and a 10%-off coupon. Since you'll never fit all that into a tiny space, you can make an animated GIF that cycles through several images automatically. Here's how:
Create the images you want to string together, with each image on its very own layer within the same Photoshop document.