Bill Atkinson was one of the earliest programmers for Apple's early Macintosh computers. His dithering algorithm was one of the hallmarks of the bitmapped screens on those computers. The algorithm takes a gray-scale image and converts it to an image that can be represented by pixels that are only black or white.
You can read about his dithering algorithm at https://beyondloom.com/blog/dither.html.
Then implement the algorithm using a gray-scale image of your own.
The Picture.java class that we've used before is helpful.