Just use the [IMG]Location of image[/IMG] BBCode (but in lowercase) like you would for any other image. .Gif images aren't videos by the way, just...images. (>o.o)>
It's my job to help the next generation, and set a good example for them. And for that I'll gladly lay down my life.
Yes, this is better suited in the This Website board. Whether or not topics like these should be in This Website or Website Design depends on how in-depth the explanation needs to be.
But anyway, it's the same for putting a .gif file as it is for putting any image on your bio. Just find the image's url and put it between the image tags:
[ image ]imageurlhere[ /image ]
I also recommending reading the thread about custom tags.