I Can't Add a Pic to My Signature...

Can anyone please tell me what I may be doing wrong? I am trying to upload a pic and gif from my computer that I found on some websites so I can add them to my signature (can you have two pics/gifs in your signature at a time?).

Thanks in advance, and in no way are these my pics! Hopefully no one will mind that I am using them...I will give them credit in my signature!

http://images.wikia.com/bakugan/images/2/27/Snivy.gif

http://fc07.deviantart.net/fs70/i/20...d1-d39jgn6.png