There are two ways:
1) When you are in a gallery folder you can upload to there is a "upload image" button on top of it.
2) You can see a big news box on top of the forum (but it's only displayed on the front page). The upload link for the current contest is in it as well for quick access.
But remember you can only upload pictures to the wish voting album and current contest (from the 1st of a month till the 15th).
If you want to show other SP-Studio pictures you have to earn your own user gallery by scoring high in a contest. Unfortunately I have to do it that way because of my limited space.
But you do not need your own gallery here to present your pictures in the forum. You can upload them anywhere on the web (for example at http://imageshack.us/
) and just link to them by using a code like this:
The url just needs to be replaced by the url of your picture.