MONOCHROME+ GRAPHICS:
The challenge is to draw a 2 color picture with a restricted amount of an optional 3rd color.

Hi-res bitmap graphics with these restrictions:
- 2 base colors may be used freely in the entire picture
- In addition, at most one of the following:
- 1 additional color may be used in a maximum of 63 of the 1000 available color blocks, or
- 8 unexpanded sprites (or fewer), using 1 additional color, distributed freely in the screen area
- Borders must be closed and the border area must be solid color in one of the 3 colors (either one of the 2 base colors or the 1 additional color)
- No rastersplits or other color changes

Raistlin coded a tool for us that automatically handles the sprites and complile a .PRG if you feed it with a .PNG image that meets the restrictions above.
You can also use this tool to count the char-blocks used for the 3:rd colour if you go for plain hires.
https://c64gfx.com/monochromeplus/