A 2MG file is a disk image created from an Apple IIGS floppy disk. It contains an exact copy of the data from the disk, saved in a single file.

The Apple IIGS was a late model Apple II system, released in 1986. It was the first Apple computer to have a color interface and became a popular productivity and gaming platform. The "GS" part of the name stands for Graphics and Sound, since the Apple IIGS had significantly more advanced audio/video capabilities than previous Apple II models.