Making .cdi or .ngr

i have a backed up game that is more than 1 session and i need to make it either a cdi file or a ngr file, i tryed disk juggler to make a cdi image but it froze on me?? i have nero but i need to know how to make a .ngr file?
is there any other program i could use???
pls help, anything is better than nothing…:confused:

menu “select recorder” —>select image recorder
then click on “copy” icon.
when the process start,nero ask you where put the image that will be created…