You mean you want to have a pic in your sig? I'm going by the title of the thread.
You need to find the pic you want, host it on a website, then you can link it to your sig. Click on your username at the top of the page, then click Edit My Signature. You need to link the pic, to do that you must get the URL of the pic which you get by right-clicking the pic, scroll down to properties, copying the URL, then pasting it using tags.
So using the logo here as an example -
[img]http://forums.justcommodores.com//style_images/1/logo4.gif[/img*]
Remove the * though. It should give you this.
Then you add it to your sig. Not all pics can be linked.
Hope that helps.