vBGallery => Edit / Add Categories => Category Options
Act as Members' Category
When set to 'Yes', any uploads to this category will automatically be placed in a sub-category named after the user who uploaded the file.
Allow Users to Create Sub-Categories
With these 2 settings set to YES on the same category should make all image uploaded appear under their username. If there are categories made by a user they will also show up when the username is selected.