You were very close. You would think if you got that close you should at least get partial credit and get part of an image. Copy this code in place of what you have and it should be fine. It will also be within the clipart guidelines for signatures.
<img height="200" src="http://members.aol.com/_ht_a/vltdisney/yensid.gif">
That code will give you this.
<img height="200" src="http://members.aol.com/_ht_a/vltdisney/yensid.gif">