The following rows of images should look alike. They only differ in the type of JPEG compression.
The first line of images is in color, and the second is grayscale.
For each line the left image is compressed as "baseline", the center image as "baseline optimized" and the right image as "progressive".
The images contain transparency information. The color images contain an 8-bit alpha-channel, and the grayscale images contain a 1-bit alpha-channel. The result should look identical and the background should shine through. The background of the middle images is light blue and for the right images darkish yellow.