read 3rd paragraph of step #1 here:

http://ghost.radified.com/ghost_2.htm

if u image a 10gb file. the first 2gb (1.99gb) gets a *.gho extension. the other four (2gb) files will all get *.ghs extensions. if you check image integrity of the *.gho file, ghost is smart enough to verify all the associated *.ghs files. ghost seees them as part of one file, but merely has to break them up into 2gb parts, cuz ghost works from dos and dos does not support files larger than 2gb. it's the same thing when working with large chunks of video with fat32, if you edit vdo. many editing programs break up the vdo into 2gb files, but the editing app (such as premiere) will still view the all associated files as a single large file.