Click on the Gallery link in the Menu on the left hand side of your screen (the multi-coloured "gallery" link), and this will open up the new gallery in a separate window.
You will need to register and confirm your registration via an automated email system (don't worry, there is no waiting period involved, unlike registration for the Forum)
It's probably best to match your Forum user ID with your Gallery user ID, so people know who's posted what.
Apparently people aren't crazy about the colour combo
I'll look into changing it some time soon