The bas to animation is to make your base layer. Take for example that banner. The base image is the two angels of death with the text. To understand a gif, you gotta know this simple logic. All it is is an image that replaces an image that replaces an image, ect. To add for example of the lightning bolt, you take your base image, make a copy if it. Find a pcture of a lightning bolt with an alpha background, and copy it so you now 2 of each. Set two aside. To make the lightning flash, I simply took a base copy, lined up.a bolt, then dropped its opacity to about 20%. Merge it down. Make another copy of your clean base and bolt, knock the bolt down to 40%, then 60%, then 100%, then 60%, 40%, 20%, gone. You'll end up with like 6 images of a bolt starting out light and getting brighter then fading. Go to filter, drop down to animation, then playback. Click play.
See is that helped. Just play around with it