What you're saying is only true for lossless compression, if you're fine discarding data you can compress anything. Try it yourself: magick -size 512x512 x

What you're saying is only true for lossless compression, if you're fine discarding data you can compress anything. Try it yourself: magick -size 512x512 xc:gray +noise Random noise.png magick noise.png -interlace Plane -quality 75 compressed_noise.jpg Result is ~380k smaller and doesn't look much different at 100%.