Champion, if you are providing the help of your system as HTML files, then these files do not have to be accessible from the application. The help system just needs to be accessible from the application if it is within the application.
Now, you don't have to use icons, but if you still want to use them, how are you doing to retrieve the images? Try doing something like getClass().getResource(imagePath) to get the java.net.URL and build the ImageIcon.
the weird thing is, when running the application in my IDE, everything is fine.
When running it as an executable jar file it works but I cannot see any icons and my userguide.html (being displayed in a JDialog) anymore.
When analysing this with logs I got the following:
when running it in the IDE the current working directory is where the starting class is located.
when running it as part of a jar file the current working directory changes to the location the jar-file is placed.
So my relative paths don't match any more. So how can I address a jar-file when specifying a relative path?