In order to be able to view the contents of a partition or an image file, it must be mounted first.
Under Puppy, partitions can be mounted through desktop. However, in order to mount image files, you'll have to click them in ROX-Filer.
When you no longer want access to the contents of a partition or an image file, you can unmount it.
Under Puppy, partitions can be unmounted through desktop, but image files can be unmounted by clicking them in ROX-Filer.