[Darksider]

Is there a program that will let me add files to an existing dmg or toast images?

[tooki]

Just mount the disc image as read-write and you can add/remove files in the Finder, just like any disk.

tooki

[TETENAL]

Well, you need to create the disk image as read/write to be able to add files to it. There is no way to add files to a read only disk image. Tip: if you create a "sparse disk image" this disk image will only be as small as needed and grow (up to the specified size) as you add files. When you remove files from it it can also be shrunk again with a Terminal command.

[larkost]

The trick is to go into Disk Utility, create a read/write disk image big enough (extra space will be removed later) to hold the contents of the old disk image (not just the size of the compressed version... mount the image and then get the size of the mounted volume). Then mount both old and new, and go to the "Restore" tab. Drag the mounted volume of the old into source and the mounted volume of the new into destination, and hit "Restore". This will copy everything over.

Now just use the read/write as if it were a HD and make the changes you want to.

Finally, when you have made all your changes, unmount the new image. Go back into disk utility and use the "Convert" button from the toolbar to create another version of this image as a compressed image.