In the Save for Web dialog box, ensure that GIF is selected (found at the top) and Looping ... highlight, background, and ...

If you want to import some transparent images to your GIF animation, you can do so using the File > Open as Layers option. In case you have images with a solid background but you want to add them ...

Whichever way you pronounce it, there is something technical to keep in mind: GIF has become a byword for embeddable files that play a short animation on loop ... color and the background as ...