They come in a multitude of formats and variants, and are used throughout macOS and apps. How do you use them, and what should be wary of?
DMG
So how can a VM of 119.6 GB fit in a 100 GB container? How sparse files can make VMs and disk images smaller on disk.
Disk images originated in the 1960s, and are still valuable tools in modern macOS. They have their limitations, though, and in some cases should be replaced by APFS volumes.
They have more options than most new cars. What are they, how do you use them, how to pick the most appropriate, and which tools to use.
So many different types, from read-only disk image .dmg files, to sparse bundles and DVD/CD-R masters. Which to use, and how to create them?
The Eclectic Light Company 