A DMG Installer is convenient way to provide end-users a simple way to install an application bundle. They are basically a folder with a shortcut to the Applications directory but they can be customized with icons, backgrounds, and layout properties. A DMG file (.dmg) is a Mac OS X Disk Image file and it is used to package files or folders providing compression, encryption, and read-only to the package.
##Creating the DMG file
#Disk Utility
Type Disk Utility
into Spotlite CMD+SPACEBAR from Finder
or from Terminal:
open /Applications/Utilities/Disk\ Utility.app/
File -> New -> Disk Image from Folder or CMD+SHIFT+N
Select the folder myapp.app/
when prompted then click Image
.
In the Save As
field enter a name for the file like myapp.dmg
.
From the Image Format
drop-down select read/write
then click Save
.
#Edit Folder Preferences Mount the dmg and open it by double-clicking the file in Finder or from Terminal:
open myapp.dmg
open /Volumes/myapp/
Create a link/shortcut to /Applications folder by right-clicking
on the Applications
folder and selecting Make Alias
then drag it into
the dmg folder or from Terminal:
cd /Volumes/myapp/
ln -s /Applications Applications
In Finder press CMD+1 to switch to icon view and arrange icons as needed.
Press CMD+J to show the View Options window and adjust view settings as needed.
From Background:
section choose Picture
then
Drag and drop the image you want to use as the
background where it says Drag image here
.
Unmount/Eject the dmg when finished with View Options or from Terminal:
umount /Volumes/myapp/
#Compress and convert to Read-only
From Disk Utility right-click on myapp.dmg disk image and
select Convert "myapp.dmg"
.
In the Save As
field enter a new name for the file like myappfinal.dmg
.
From the Image Formate
drop-down select read-only
then click Save
or from Terminal:
hdiutil convert -format UDZO -o myappfinal.dmg myapp.dmg
#FIN Congratulations you are finished! Mount the new dmg to verify it is working properly.
Not exactly sure of the ask about "option to convert dmg", but if you can mount the "image" and then use Disk Utility to create a DMG from it should work. The option to create a DMG is still there, at least on macOS Sequoia (15.x).
File > New Image > ...
this will create a new DMG either a blank on or from folder or a mounted volume, if I believe it has a compatible file system format.