how to create a dmg file that expands based on the space required?

[mrgreeneyes]

how can I create a dmg file that will auto expand in size to fit all my files I am adding to it?

it's a pain to have to create a bigger dmg each time I need to add files to it.

I am using a dmg file system to backup all my roms that I download.

 

[ab22]

Have you tried a Sparse disk image ?.

'...Creates an expandable file that shrinks and grows as needed. No additional space is used. Uses the .sparseimage file extension.'

Create a disk image using Disk Utility on Mac

Use Disk Utility on your Mac to create a disk image.

support.apple.com