Sparse image
TYPE OF DISK IMAGE FILE USED ON MACOS THAT GROWS IN SIZE AS THE USER ADDS DATA TO THE IMAGE
Sparse disk image; .sparseimage format; Sparse bundle; .sparseimage
A sparse image is a type of disk image file used on macOS that grows in size as the user adds data to the image, taking up only as much disk space as stored in it. Encrypted sparse image files are used to secure a user's home directory by the FileVault feature in Mac OS X Snow Leopard and earlier.