Resize a disk image using Disk Utility on Mac
You can read and write to a disk image or change its size. For example, you can make a disk image smaller to save disk space or make it larger to store more information on it.
Note: To resize a disk image, first close the image by ejecting it, so it doesn’t appear in the sidebar when you open Disk Utility.
In the Disk Utility app on your Mac, choose Images > Resize, select the disk image file you want to resize, then click Open.
Type a new size, then click Resize.