Because the instructions, “draw a brick here, a pipe there, here are the rules for how jumping works, etc.” are smaller than “these pixels are blue, that one is orange, that one is white, etc.”
Also, the jpeg is going to store each pixel as a 8bit x3, Rgb (255 *3), color pallette for the color code, whereas the nes was limited to only 56 colors.
Because the instructions, “draw a brick here, a pipe there, here are the rules for how jumping works, etc.” are smaller than “these pixels are blue, that one is orange, that one is white, etc.”
Also, the jpeg is going to store each pixel as a 8bit x3, Rgb (255 *3), color pallette for the color code, whereas the nes was limited to only 56 colors.
Also, this jpeg has multiple pixels where there would only be one pixel on the nes
More: that palette was hard coded and the actual in use palettes were even smaller subsets of the system palette to reduce memory demand