My participation in the Compo over time
For my latest two entries, I used eight colored (3-bit) images. They are stored as text strings, encoded specifically to not use special ASCII characters. This makes the data suitable for archiving. The method for storing was invented by one of the jam participants, @xem. I extended his miniPixelArt tool and made it possible to load image files:
Tip: open the Image Encryptor in a new window in order to maintain a history of the loaded images.
In Super Bunny Strikes Back I have two playable main characters and they comprise significant portion of the sprites used in the game. I knew there won't be much space and decided not to cut from their 6-frame jumping animations, but rather reduce the enemy creatures count and diverse them with different color pallets (changing colors is quite trivial if you use the Image Encryptor).
The sprites have 7 colors and transparency. In addition I use a special approach to mimic a contour by applying a drop shadow filter on all images. This comes with a bit of limitation on what can be drawn with the sprites - for example you can't place two pixels of contour vertically next to each other. But with a little effort this can be walked around with suitable pixel art.