Because the person creating the image didn’t take the time to optimize the image. It’s probably just a PNG or a JPEG, which is way overkill for representing a NES frame.
Other commenters have mentioned that the NES has 56 colors and uses tiles to draw the frame. If you took the same approach (maybe embedding a GIF tile in an SVG), you could cut down the size of the modern image significantly.
PNG is fine for this. A palletized PNG on max compression would be smaller than the game and totally lossless unlike this. First you gotta take this image and map/quantize it to the original palette though to destroy the JPEG artifacts, which produce colors in between ones that would have existed in the game’s output.
Because the person creating the image didn’t take the time to optimize the image. It’s probably just a PNG or a JPEG, which is way overkill for representing a NES frame.
Other commenters have mentioned that the NES has 56 colors and uses tiles to draw the frame. If you took the same approach (maybe embedding a GIF tile in an SVG), you could cut down the size of the modern image significantly.
PNG is fine for this. A palletized PNG on max compression would be smaller than the game and totally lossless unlike this. First you gotta take this image and map/quantize it to the original palette though to destroy the JPEG artifacts, which produce colors in between ones that would have existed in the game’s output.