I don't know about your compression numbers. I just created a 1000x1000 pixel gif with a number 1 in the middle, and it compressed to 4790 bytes equals 38320 b

I don't know about your compression numbers. I just created a 1000x1000 pixel gif with a number 1 in the middle, and it compressed to 4790 bytes equals 38320 bits. So, 1,000,000 pixels divided by 38320 bits means 26 pixels per bit. https://en.wikipedia.org/wiki/GIF https://en.wikipedia.org/wiki/GIF suggests that long runs of a single color compress rather well.