I use a program called Alcohol 120%. It also allows you to mount images on virtual drives. There are many programs that open image files but i cant think of any others off the top of my head.
ISO files can be opened in WinRAR as well.
Try google to find other programs
first, what type of image file?
second you will need an application that can open and/or edit that type of picture file...
what do you mean on a disc? floppy, cd, hd?
**edit** still on first cup of coffee... are you talking drive immage?