since i found out how to giffs ive had a message on how i did it so heres how i did it
go to a sight like giff bucket or where ever
download the giffs you want and create a photo album on your profile on 360 haven
upload downloaded giffs
when dats done right click on photo in photo album and click copy url
go to signature click on space where you want it then click the picture of a tree at top of writing box it says image
then paste the url you copied from giff and your done