If you go to the Tech Board, they have detailed instructions about how to add those things to your signature.
But there's a big caution out there right now because the Dis Boards have been experiencing problems in the last few weeks and in an effort to improve reliability and response times, they've had to cut back on some of the extra features.
In order to include photographs and clipart in our posts, you have to have access to a Website that allows you to use active links from their sites. Becuase of rising costs and increased number of users, most sites do not allow you to link to them. The Dis Boards allowed us to do that by providing free Websites to users, but it has become an overwhelming burden for them, so access to those Websites has been cut off, pending a study to determine if it's at all possible in the future.
So my answer is, check out the top of the Tech Boards for the directions you need, but it isn't possible to do new Websites or to add new items to existing sites right now. It might be possible in the near future, but they'll let us know.