When a build or a test build is started, important status messages are displayed in the text area labeled build output. A progress bar appears in the status bar of install4j's main menu which indicates what percentage of the total build has been completed so far. The build process is asychroneous, so you can change to other steps while it is running. The status bar will inform you when the build process has finished.
With the standard setting, all media files will be built. If you select the radio button build selected, only the media files that are selected in the adjacent list will be built.
These settings are persistent and are saved in your project file, however, when you build from the command line, your build selection will be ignored unless you specify a special parameter. Please see the help on the command line compiler options for further details.