Yes, using a lossy image format for pixel art or images with a small number of colors in general has always been a a bad idea. Many people do not see the artefa

Yes, using a lossy image format for pixel art or images with a small number of colors in general has always been a a bad idea. Many people do not see the artefacts, but they are there, and the fact that the file size is even bigger with lower quality does not make it better. BTW, the images also contain a grid, so you would need at least three colors, which requires 2 bit per pixel before compression.