This article will explain how to add a script to Nautilus so that you can easly mount and unmount ISO files in most linux distros running Gnome (it needs Nautilus to show the desktop). After a ISO file has been mounted, a shortcut icon will appear on your desktop which you can right click to unmount. Also, the script will automatically remove the desktop icon after you have unmounted the image (ISO). Look here for installation instructions for KDE.