This nifty assignment submission describes two interrelated image compression assignments: one which asks students to implement an image decoder, and one which asks students to implement an image encoder. Students work with a text-based image format developed for the assignment which was based on the Quite OK Image format. Compression is achieved by representing pixels as a difference from the immediately preceding pixel, as a copy of a pixel that has been encountered previously, and as a run of several identical pixels. A collection of contrived images was provided that used only a subset of the three compression approaches, along with a collection of ‘real’ images that combined all three approaches. Each variation of the assignment was used successfully with CS1 students.