You simply use your fancy HTML editor!
When you're replying to a thread, look up^^ you should see a tool bar of various options. There's Bold, Italic, Underline, 3 justification buttons and then beside that... Insert Media! It looks kind of like a little painting of the mountains and a sun...
Which will open a popup of the photo gallery. Choose whether you want to add a picture from your own gallery or the public one.
Simply click on the image... and BAM!
It will instantly drop into your message re-sized to 250 wide. You can just click on it, grab the corners and re-size the image to whatever you want.
If you want to get crazy, hit up the centering to make it look extra pimp!
Soon there will be the ability to do flash videos in the same manner... which will be extra uber cool!
Check it for some good content and a view into the way skiing should be.