PLS HELP

That my friend is called Graphics Interchange Format, also known as GIF.
Here's an example of a GIF usable as a pfp:


EDIT: In a nutshell, you can use ezgif and make one yourself, etc.

Adding to what Zydrolic said, you could also animate it yourself using the scratch editor and recording it with any recording tool that can save to gif and set it as your profile picture. Just make sure it's under 512KB (kilobytes) big and less than or equal to 500x500 resolution.

do the same thing as you do with the static image but with a gif

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Jokes aside, use a .gif file that's under 500x500 and 512kb.
You can use websites like ezgif to make it.

you can also find other accounts with gifs and save them