creating .dmg for install with background

make a new folder (for this example: AppBundle)

drag the finished application file (.app) and any other files you want the user to have into AppBundle

create a background image (png file)

using the terminal, create a hidden directory named .background in AppBundle

copy the background image into the .background folder

open Disk Utility

drag the AppBundle folder onto the Disk Utility icon, or use File → New → Disk Image from Folder… and select AppBundle

set the Image Format to read/write, and don't use encryption

save the dmg file as “AppBundle read-write.dmg”

mount (open) the “AppBundle read-write.dmg” file in the Finder

press command-j to bring up the window settings dialog

click “This window only” so the changes won't modify any other folders

in the Background section, select Picture

since the image is in a hidden folder, use command-shift-g to bring up the Go To Folder sheet

type the full page to the background folder: /Volumes/AppBundle/.background and click Go

select the background image, and click Select

once you have the window looking exactly the way you want users to see it, unmount the dmg file (eject)

AppBundle.dmg should open up with your view settings intact