Compressed disk image created with WinImage, a disk image utility; contains an exact copy of a physical disk, but is also compressed to save disk space; can be mounted as a physical disk when opened with WinImage. NOTE: Uncompressed disk images are saved as .IMA files.
The IMZ file extension is used for compressed version of IMA floppy disk images. This format was widespread when floppy disk were the mainstream portable media, until replaced by CDs. But even today, some linux-based system still utilize floppy disks.