Make a DMG

Thanks for the help. That was fast. Here is the help page in Disk Utillity:

1. In the Disk Utility app on your Mac, choose File > New Image > Blank Image.
2. Enter a filename for the disk image, add tags if necessary, then choose where to save it.
3. This is the name that appears in the Finder, where you save the disk image file before opening it.
4. In the Name field, enter the name for the disk image.
5. This is the name that appears on your desktop and in the Finder sidebar, after you open the disk image.
6. In the Size field, enter a size for the disk image.
7. Click the Format pop-up menu, then choose the format for the disk:

• • If the disk image will be used with a Mac that has a solid state drive (SSD) and uses macOS 10.13 or later, choose APFS or APFS (Case-sensitive).
  • If the disk image will be used with a Mac with macOS 10.12 or earlier, choose Mac OS Extended (Journaled) or Mac OS Extended (Case-sensitive, Journaled).
  • If the disk image will be used with a Mac or Windows computer and is 32 GB or less, choose MS-DOS (FAT); if it’s over 32 GB, choose ExFAT.

1. To encrypt the disk image, click the Encryption pop-up menu, then choose an encryption option.
2. Click the Partitions pop-up menu, then choose a partition layout.
3. Click the Image Format pop-up menu, then choose an option:

• • Sparse bundle disk image: Same as a sparse disk image (below), but the directory data for the image is stored differently. Uses the .sparsebundle file extension.
  • Sparse disk image: Creates an expandable file that shrinks and grows as needed. No additional space is used. Uses the .sparseimage file extension.
  • Read/write disk image: Allows you to add files to the disk image after it’s created. Uses the .dmg file extension.
  • DVD/CD master: Changes the size of the image to 177 MB (CD 8 cm). Uses the .cdr file extension.

1. Click Save, then click Done.