Duracell is correct. .gi stands for global image, and could be for either. However, if the image is of a CD, it couldn't be burned to a DVD, and vice versa. For instance, you couldn't burn an audio CD image to a DVD, just as you couldn't burn a SVCD image to a DVD. Even if the files were there, they wouldn't function properly. So, it really depends on what the global image is of.