I got lazy in my graphics design, so I made a program to convert regular images to 4-level greyscale images in Racket. The source code is below, for anyone who cares.
#lang racket (require picturing-programs) (require racket/math) (require racket/draw) (define (draw image) (define (grey-function x y red green blue) (define n (floor (+ (* .587 green) (* .299 red) (* .114 blue)))) (cond [(< n 42.5) 0] [(< n 127.5) 85] [(< n 212.5) 170] [else 255] )) (map3-image grey-function grey-function grey-function (scale .5 image)))
I scaled the images down, since the calculator screen is so small. This can be adjusted. The brightness/darkness can be adjusted by changing the 42.5, 127.5, and 212.5.
To run the program, you would need an environment (DrRacket). A bit annoying, but oh well.
I might make a similar program in Java soon.
Fire Emblem for TI 83/4+ Progress: Demo: 75% Total: 40% Postponed indefinitely