How to Make a Macintosh Disk Image (.dmg) Smaller

Do you have a disk image (filename.dmg) that is taking up too much disk space, or storing unwanted or redundant files? You can delete some of the files and resize the .dmg file to save space.

The easiest thing to do is just open/mount the .dmg file and copy everything in it to a folder of the same name on your hard drive. Toss out what you don't need anymore, and then open Disk Copy from your Applications > Utilities menu, and choose the menu items below:



Then, find the folder you just created with the disk images items in it, and choose it for the new disk image.

Save the new one with a different name elsewhere on your hard drive, and you will now have a resized disk image.

Now you can toss out your larger one.