To create a gallery page, simply create a page using your login id or real name as the name (or a prefix if you want multiple pages) and make sure that it is assigned the category Gallery and no other category:
Please make sure that the images appearing in these galleries also have a name that is prefixed with your login using the form: <login>-<image name>. e.g. If Fred Nurk wanted to upload an image called 'my painted figure.jpg' then it would be named Fred Nurk-my painted figure.jpg.
Hint: If you are unsure about how to structure your new page, copy the wiki text from an existing one and modify it to suit.