Go to the Tech boards here on the DIS and check out the 2nd and 4th posts (labeled Important), at the top of the list.
The 2nd is by J.Cricket and tells how to add the countdown timer to your signature.
The 4th is the FAQ's and from there you can check several posts on how to add clip art to your post. (Basically in a nutshell, you have to have an internet site you can download your clip art onto. The art will then have it's own internet address (called URL which means Universal Resource Locator (I think?). You then add an image tag to the URL address so it shows up as a picture in your post and not as a link. Put that line of code in your post, and presto, a picture will show.
It may sound complicated, but it's really not too bad. After you go through the FAQ's, if you have any questions, post them on the tech board. The fine folks there will be glad to help you out.