I'm a (very) amateur game developer and I'm working with IntellijIDEA and Java Swing to create really simple stuff. What I'm wondering are what options I have available for packaging all the various .java files, graphics, etc. in a professional way that I can then easily give to friends or others. What's recommended or most often used? Intellij has a way of creating a .jar file for a program but I've had difficulties getting it to work with images and other resources. Any help would be appreciated.

You can try packing the Java runtime into the distribution, which will allow anyone who doesn’t have Java installed run the program (more specifically, it also would override any already installed Java runtimes as well).

But your resources problem is unrelated, and is more related to the lack of understanding on how Java resources work. Which is probably top priority at the moment, compared to distributing the game :P.