ThunderScan was a hardware device that replaced the ink cartridge in
an ImageWriter printer that turned it into a (very slow) black and
white scanner.

Download #1 contains a Disc Copy 4.2 image of version 2.5 dating March
1986

Download #2 contains a folder copy of version 3.2 of ThunderScan.

Download #3 contains a disk image (including System Folder) of version
5.1

For more information about ThunderScan, see [Andy Hertzfeld's
blog][1].

Compatibility
Architecture: 68k

Requires hardware device to test, but appears to work under System
7.5.5.

  [1]: https://www.folklore.org/StoryView.py?project=Macintosh&story=Thunderscan.txt