To save the content of the desktop as work, which you can
go back to later and continue to modify, click on the icon "Save work to file" 
. The
standard dialog box for saving a file will appear.
Note: The difference between the functions "Save image to file" and "Save work to file" is that when you save work, all the layers in the work area will be saved as well, meaning you can still go back and do further work with any of the layers. When you save an image to file, the content of the working area is saved as a flat picture and no further work with separate layers is possible later on.
