Two ways to post photos... that I know of!
1. Use the IMG button just below all of the smileys when you hit reply. If you do this, the site of your pic must be linkable. Several are, several are not.
2. Upload a pic from your home computer. If you do this, you must scroll down to below where you reply, but just above where it says "submit reply", and browse your computer til you find the pic. Click on it, it will show up as an attached file. To use this, it can not be above the max size of 102,400 bytes.