Jack,
After your type out your message, hit the paperclip icon (it's just to the right of the smiley face. You should see a window open up like this:
When you see this, hit the browse button on the first line. You will get a box that you can browse your computer and find the picture you want. When you click the picture and then OK, you will be back at this window. The first line should be filled in with the path to your picture on your cpu. When you have that, hit the Upload button. You should then get a confirmation saying it's been uploaded. |