1. Set up your "Prototype" Mac. The image you create will be a clone of this Mac.
   
   1. You can do this either using the hard disk of a Mac or by using a partition on an external drive.
   2. Try to start from an official Mac install disk. If you don't, you are rolling the dice.
   3. Make sure that you do ALL of the Apple system updates and application updates.
   4. Verify that it has everything on it that you need: a local admin user, local user (typically 'student' or 'teacher'), drivers, applications, etc.
   5. If you need OS9, put the OS9 System Folder and OS9 applications on that you need and check that this works.
   6. Check that the network, including wireless passwords and proxies is set up properly.
   7. Set up the Dock as you want it.
   8. TEST, TEST, TEST ! Make sure everything actually works!
   9. If you have ever logged on using Active Directory, be sure to delete any of these accounts left on the disk under "/Users".
   10. Delete anything from the "/Users/Shared" account that you don't want there.
   11. EMPTY THE TRASH!!
   12. REPAIR PERMISSIONS !! Use "Disk Utility" ( /Applications/Utilities ).
   
   
2. Mount the "Prototype" disk or partition and check your access to it.
   1. If your "Prototype" Mac was created on the internal hard drive of a real Mac you have two choices as to how to proceed:
      1. Choice 1: Boot up the "Prototype" Mac from an external drive (hold down the "Option" key during reboot). You will perform all of the actions on the "Prototype" Mac hardware and write the resulting files to the external boot disk.
      2. Choice 2: Boot the "Prototype" Mac into "Target" mode (hold down the "t" key during reboot). You will need another Mac, which you will connect to the "Prototype" Mac with a firewire cable. Use the disk of the "Prototype" Mac as the source for the new image, perform all work on the other Mac, and save the resulting image on the disk of the other Mac.
   2. If your "Prototype" Mac was created on a partition of an external disk, use this partition as the source for the new image.
   3. Make sure that you can see the boot partition of the "Prototype" Mac.
   4. Do a "Get Info" on the "Prototype" Mac and be ABSOLUTELY CERTAIN that the "Ignore ownership on the volume" box is NOT checked. Otherwise the ownership on the image will not be enabled and the resulting image will not produce bootable partitions.
   
   
3. Create a read/write image of the "Prototype" Mac boot drive or partition.
   1. In OSX 10.4 you do this in "Disk Utility" by selecting the boot partition of the "Prototype" Mac using:
      File => New => Disk Image from Folder"
      The reason you are choosing "From Folder" is that although this is slower, it gives an image that will fit on a larger drive and can "stretch" to fill the new volume correctly. Without the ability to "stretch" you will have to use the "file copy" mode of ASR, and that will result in a much slower restore.
   2. Make absolutely sure that you are creating a read/write image.
   3. Choose a place to save the resulting image. NOT on the "Prototype" Mac drive or partition!!
   4. Give the new image a meaningful name.
   5. Start creating the image.
   6. "Disk Utility" will create, and then copy, the new file.
   
   
4. Convert the new image to a compressed image.
   1. The new image that you have just created should be visible in the little box on the left of the "Disk Utility" panel.
   2. Select the new image.
   3. Choose a different name so that you don't overwrite the image you just created.
   4. Use "Disk Utility" Images => Convert.
   5. ASR needs either a compressed or read only image to do the restore. Compressed takes up less space when you store the image.
   
   
5. Scan the image for restore.
   
   1. use "Disk Utility" Scan Image for Restore.
      The reason you are doing this is so that check sums will be incorporated in the image to allow checking at restore time.
      The progress bar will stay as a "Blue Barber Pole" - it never reports progress correctly until it finishes.
   
   
6. Store the new image in a safe, backed up place.

Congratulations. You are now ready to use the new image to clone the "Prototype" Mac.

- Bob Beeman.

PS: How to make a Flash Drive bootable Disk for 10.5: How to Create a Bootable Mac OS X USB Disk

Create an Emergency Boot Device Using a USB Flash Drive OSX 10.5x or greater.