You are absolutely right, sorry. It was late yesterday and I was more writing this as a reminder to myself. I stumbled over this, while trying to get stratagem to work, which died throwing an IllegalArgumentException (ImageIO did not throw the caught IOException, but the IAE instead).
The loaded images are in media.jar, which can be found in the resources folder.
I didn't find the icon in question, so I thought it might be legacy code. Maybe the media.jar should be extracted in the SVN-project, so one can find the resources via common project find and add new resources if necessary. Also I would vote for a toplevel package "org.xith3d.resources" to follow common deployment rules.
They are loaded from ClassLoader, because it doesn't load them through getClass().getResource().
I should have known that by myself but was distracted by the "missing" icon

. Btw. how does the threads ContextClassloader behave different from the classes Classloader?
Which way would you suggest to handle the IOException in DisplayOptions line #793?
It should be common practice to log a warning for such exception. At best containing a hint what might be the problem (e.g. "Make sure the media.jar is on your classpath"). If that's not desirable due to performance issues (and only then) there should be a comment in the catch block containing the reason for ignoring the exception and where possible a similar hint to the problem like described above.