Nero with the general production of hard disk ISO image file

How to use nero to the production of ordinary hard disk ISO image file??

Halo, nero is used to burn discs, is the mirror Graver file space on CD-ROM with the image produced by scattering
tool looks like WinISO
will be able to use the NERO image of the virtual burner can burn data to CD-ROM drives NRG suffix known as the CD-ROM image file

ISO and NRG are not the same as long as you use the virtual drive can be read on the trip, NERO can burn ~! ISO must

do not?