Save the one that you like to your photo bucket service, and then in your signature post the link like it is a picture. I hope that makes sense.
Yes right-click on the one you like and select "save image as" and make sure you save it as a gif and that you save it somewhere that you can find. Then upload that gif to photobucket or whatever you use for pics on this site. Copy and paste the image link just like you do with other pics and hopefully that should work.
I see you got it to work!
I don't think it hurts to have options! I'm pretty sure I've seen someone with the other style other than you, so I think both are getting used.