[eluser]falkencreative[/eluser]
I'm sure there are different ways to approach this... One way:
-- In your users table in the database, each user should have a unique ID (primary key, auto-increment)
-- You could have an images table in the database that could contain the image ID (primary key, auto-increment), the related user ID (so you know which user the image it relates to) and the url to the uploaded image
If you needed to get all the images associated with a specific user, you could search the images table and show all the images that have the correct associated user id.
If users have multiple galleries that you need to keep organized, you might also need a galleries table, and then need a column in your images database that included the id # of the gallery the image was a part of.