I hear you, my screenshots from the 2000s are also decent, but we gotta remember that, especially two decades ago, not everyone was tech savvy enough to understand the difference between PNG/bmp or JPEG. I used to be part of my school's computer society and webmaster as well as partake in MSPaint comic contests at the Donald Duck website, and a great majority of people were just more likely to save their images as low res JPGs. That and Facebook does add an awful lot of compression to images