Whenever I export an image from Krita, it's always like 20-40 mb, which is like pretty big for me since I'm used to using my ipad to draw digitally and that usually is in the few hundred kilobyte range, a megabyte maybe but that's rare. I don't have to worry about storage on my PC since it has 4 terabytes but I still like posting my art to the internet and the sites I like posting to tend to have pretty strict posting limits, like less than half of what the file sizes of my art usually are. Compressing my art works and it doesn't show any (noticeable) quality decreases.