Disk Utility 12.x: Resize a disk image
If you can read from and write to a disk image, you can change its size. For example, you can make it smaller if you need to save disk space or make it larger to store more information in it.
- Open Disk Utility, in the Utilities folder in Launchpad.
- Select the disk image if it appears in the list at the left, and then click Resize Image in the toolbar.
Otherwise, click Resize in the toolbar, and then select a disk image in the dialog that appears.
- Select a new size.