If you mean CDs with pictures, were they once readable on your friend's PC?
(It can happen with files on HD or floppy as well)
If this is a first time, then either the pics are not "associated with an application" or perhaps the CD is not readable on that PC's configuration.
Try finding the pic you want in "my Computer" and right click on that file. Then choose "open with" and select the software you expect to open it.
Have you tried the pics with another PC?
If you have no luck post back with the full subscript of the files eg .gif, .tiff, .jpg etc.