How to Make a DMG File on a Mac

Creating a DMG File Manually

1. 
   Create a New Folder for your files. Place the files you would like in your disk image into this new folder for easy access later in the process.
2. 
   Right-click (or CTRL-Click) the folder and select "Get Info." Note the size of its contents so you can know how large you will need to make your DMG File.
3. 
   Open "Disk Utility." Go to "Applications" and then "Utilities." "Disk Utility" will show up in the dropdown menu.
4. 
   Click the "New Image" icon to create a new disk image. You can also accomplish this by selecting "File," "New," and then Blank Disk Image." Enter a name for the Image and identify the size you would like for the DMG File. It only needs to be large enough to fit the files you are trying to store. Here you will have the option to encrypt the folder. If you do not wish to encrypt the folder, select "None."
5. 
   Select "Create." This will create the DMG File. You should be able to immediately see it appear on your desktop or in the left-hand column of your finder window. Once you have done so, exit out of Disk Utilities.
6. 
   Fill your newly created disk. You can do this by simply selected the files you want and dragging them to the DMG file.