Well, Ballcoach, first you have to "host" your digital photos through an on-line service such as Imageshack or Photobucket. Just follow their instructions.
Once you get and copy the link to your photo that site gives you, just click on the square, yellow icon (the one that looks like mountain peaks) above the place where you normally post a message.
A box will pop up. Erase anything in that box, then past the photo link you just copied.
Click "OK" and you're done!
Then just click on the submit button as you always do to place a post here.