With Nero Express you can burn a disc from a disc image or compilation that you have previously saved on the hard drive.  
To load an image file or a saved compilation for the burn process, proceed as follows: 
Click the Image, Project, Copy menu icon in the Nero Express start screen.
The copy and disc image options are displayed.
Click the Disc Image or Saved Project option.
The Open dialog window is opened.
Select the image file (*.nrg, e.g.) or saved compilation you want and click the Open button.
The selected file loads and the Final Burn Settings screen is displayed.
You have successfully loaded the image file or compilation and can now burn it.
An image refers to a single file on the hard drive that contains the image of a complete disc. A disc image can be used to create exact copies on media at a later point in time if problems occur during the write process or if no recorder is connected to your PC. The image requires as much free space on the hard drive as the contents of the original disc take up.

Loading a Disc Image or Saved Project