[mrob]

It's hardly fair to call it "terrible" when you're scaling it with non-integer ratio nearest neighbor scaling (causing uneven original pixel sizes), then compressing with a lossy algorithm designed for completely different images.

SNES (and NES) screenshots are difficult to display well on modern systems because the (S)NES had rectangular pixels instead of square pixels as used today. I recommend scaling to some large integer multiple of the original size with nearest neighbor, and then scaling to the correct aspect ratio with your favorite resampling filter. And if you insist on using JPEG compression then at least use 4:4:4 chroma subsampling - chroma artifacts are very obvious in pixel art.

I also dispute the assertion that CRT artifacts were required or intended by all graphics designer back then. Evidence: LCD based portable systems and line doubled mode 13h DOS games both used the same dithering techniques, but they had sharp pixels. And many games used dithering type patterns to represent fine detail instead of blended colors, eg. the typewriter in the background near the start of Chrono Trigger. I grew up with DOS games so I personally prefer sharp pixels.

The most important feature of a CRT is the low persistence - eliminating sample and hold blur. This is now available in fast modern LCDs with strobing backlights, or with black frame insertion displaying 60Hz content on a 120Hz monitor. It makes a very big difference for fast scrolling 2D games.