Thread: Multiple listeners? || one program or one for everyone?

Perhaps instead of JLabels, you should use JButtons (or some variant of that).

Why don't you store the skins in an array? That way you don't need a new variable for each one.

Have you looked into somehow "lazy" loading them? Meaning, only loading one when the user asks for it?

If your program runs on a website, is it an applet? If so, applets are downloaded to the client, so every client gets their own version.

I use something called: CardLayout to do this. Basically, you add each "screen" as a JPanel to the layout's list of cards. You can then swap in and out the cards programatically. So the program starts on the login screen. Once the user logs in, you swap out the login screen with the profile screen (or whatever). The states of all the "screens" do not change when you swap between them, because they are all stored in memory.

The increased memory is not significant, and it really is by far the best way of approaching the problem.

You should load the image on a different thread. Do some research on multithreading. Computational tasks (especially those that are lengthy) should not be performed on the same thread as the GUI, because doing this causes "freezing" or "lock ups". You should start a new thread, begin the process on the new thread, and then provide the user with some sort of loading message on the GUI thread. SwingWorker is a good jumping off point for this: Worker Threads and SwingWorker (The Java™ Tutorials > Creating a GUI With JFC/Swing > Concurrency in Swing)

Yes. An applet is required to run in a browser (although, be warned, Oracle is making some security changes this month which are expected to effect applets significantly). It is very similar to an Application. Applets do not have mains, but rather a class which extends from JApplet or Applet. You then specify the "main" class when you embed the applet in the browser (preferably using JNLP: Java Network Launch Protocol (The Java™ Tutorials > Deployment > Deployment In-Depth))