Some JPG implementations perform poorly when confronted with stripes that are only one or two pixels wide. See how the red is faded almost completely? The image at right was created using an early version of Paint Shop Pro with the highest quality JPG setting, but which did not allow disabling chroma subsampling. A different choice of JPG algorithm eliminates this effect at some increase in file size. See "Adobe JPG's vs. Early Paint Shop JPG's."
JPG or lossless for image archives?