Dave's code will do it. After making the button, it needs to be uploaded to a server (I saved it to my harddrive and then FTPd it to my blog site). Then link it like Dave did: <a><img /></a>. It's a tiny file but it does generate traffic that might be a concern for low bandwidth hosting plans, and some hosts prevent single image linking. If the image file were located here somewhere, the traffic would come here, but it's generally inconsequential.
