The challenge is to switch the colors to the complimentary version of themselved on the color wheel (opposite colors, i.e. green, red) so whenever the colors are inverted it looks like the original. ILLEGAL MOVES: Online Color Inverter to create final, but you can use it to help you. I never used one for this because I have a shortcut (Ctrl+Search+H) that is for Chromebooks ONLY Telling people to invert the colors to see the final (not doing a thing to the image then telling others to invert the colors) Looking up "Inverted Colors" without the quotes on an image search online. Unoriginal Pictures (only use vector images on Scratch, as it makes it a handful easier to recolor and everything) More rules will come.
If the lines get thicker than the origninal while picture editing, it's alright. It won't count against you. What does the Love-it and Favorite buttons look like in inverted colors? Click them and maybe you might see! (blue and lighter blue)