The 'edit own' permission should be all you need. Allow the user to create content of a specific node type. Put a gallery, description and any other fields on it.

The 'edit own' permission should be all you need. Allow the user to create content of a specific node type. Put a gallery, description and any other fields on it.

A little more detail:

1. Create a content type 'Pages'.
2. Make sure users can create new pages and edit own pages.
3. The user makes as much 'Pages' as he wishes.
4. Put a gallery and any other fields on the content type.

If you want to use other content types instead of fields, use entity reference.