If I'm correct, there is a bb code comand for it.
Do as following:
1. Get a gif(for example, I am going to use this: i326.photobucket.com/albums/k422/squiishychan/Sprites/snivy_zps67c6ebd2.gif)
2. put in the following: [CENTER ][IMG ]i326.photobucket.com/albums/k422/squiishychan/Sprites/snivy_zps67c6ebd2.gif[/IMG ][/CENTER ](without all the spaces)
3. Try submitting it.
It should look like this:
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[IMG]i326.photobucket.com/albums/k422/squiishychan/Sprites/snivy_zps67c6ebd2.gif[/IMG]