Photoshop is smart enough to disable chroma subsampling[1] if it will screw up the image, it looks like jpeg.io doesn't do that. One of the worst case scenario

Photoshop is smart enough to disable chroma subsampling[1] if it will screw up the image, it looks like jpeg.io doesn't do that. One of the worst case scenarios for chroma subsampling is alternating black and red lines. Some monitors/TVs do 4:2:0 by default. It can cause problems... https://plus.google.com/photos/photo/100697962438000631056/5902440355823383874?icm=false https://plus.google.com/photos/photo/100697962438000631056/5... [1] https://en.wikipedia.org/wiki/Chroma_subsampling https://en.wikipedia.org/wiki/Chroma_subsampling