New Disk Image with the Finder Selection
Disk Images are special archive files that act like disks. Double-click a disk image file and the volume it contains is mounted on the desktop, as in the example below where the volume Hubble Movies has been mounted on the desktop by double-clicking the disk image file Hubble Movies.dmg. The mounted volume has been opened and its contents are displayed in a Finder window:
Note that disk image files have a name extension of dmg. Creating disk image files is normally a complex process, but it can be made easy using Automator. Here's how...
Create the Workflow
Launch Automator, and create the following workflow (click the image to view a larger version). Be sure to set the Options of the second action, New Disk Image, to show the action view when the workflow is run. If you prefer, you can download the completed workflow file.
Save the Workflow
With the completed workflow open in Automator, choose Save as Plug-in... from the File menu. From the sheet, save as a Finder plug-in named Disk Image with Selection:
Using the Workflow
Creating a new disk image using the selected Finder items is simple, just follow these steps:
In the Finder, select the items you wish to copy into a disk image archive:
Next, you'll need to determine the combined size of the selected items. Type Command-Option-I to summon an information window for multiple items. The size of the combined items will be displayed on the top right of the information window:
Close the Information window, and run the workflow by clicking on the selected items while holding down the Control key. This will summon the Finder contextual menu, from which you select More > Automator > Disk Image with Selection. The workflow will begin to run and view window for the New Disk Image icon will be displayed in the center of your screen:
Enter a name for the new volume and the disk image file, and then select an amount from the size popup menu that is larger than the size of the selected Finder items. Try to use at least 10-percent larger volume size that the combined item size. Note that the Size to Fit size option (if you diecide to use it) will not allow for customization of the newly created volume. Also be sure to choose the option to leave the volume mounted when done.
Click the Continue button in the action view window to continue the workflow execution. Once the workfow has finished, a new volume will be mounted on the desktop displaying its contents in a Finder window:
Customizing the Window Display
Optionally, you can change the settings in Set Folder Views action in the workflow to whatever setting you prefer. In addition, any view changes you make to volume window in the Finder will be remembered the next time you open the disk image file.