DropDMG tries to determine what you want it to do based on the files or folders that you give it. For example, suppose that you’ve set the preferences to create .dmg disk images. If you give DropDMG a folder, it will create an image of the folder. If you give it a .zip, .tar.gz, or StuffIt archive, it will convert the archive into a .dmg disk image. If you give it an image in another format, DropDMG will convert it to .dmg format, using the options specified in the preferences. Conversion can also be used to add or remove license agreements or encryption, or to segment or join an existing image. If you give DropDMG a file that’s not an archive or image, DropDMG will create a new image containing just that file.
When asked to create an image from a volume, DropDMG creates a special “device image” that is an exact copy of the volume, not just its constituent files. If the volume was bootable, the image may be burned to CD or DVD and the resulting disc will also be bootable.
When given multiple files or folders, DropDMG creates a separate image or archive for each. To group multiple items into a single image or archive, move them into a new folder, and then drop it on DropDMG.
So how do you “give” DropDMG a file or folder to work with? There are several ways: