XnView Software

Decreasing the color depth of logo.png (32-bit RGBA incl. pHYs + iCCP + cHRM chunks) gives me varying results:

• XnView MP v0.53
  • Image » Change color depth...
    • Greyscale [256]
    • Dithering [none]
• XnView v1.99.6
  • Image » Convert to Grey » 256 Grey scale

Even if I remove the alpha-channel transparency first (by changing the color depth to 24 bits), MP produces different PNG output (compression level 9):

• XnView MP v0.53
  • Save as...
    • 6661 bytes
    • 8-bit greyscale
    • pHYs + iCCP + cHRM
  • Export...
    • 8179 bytes
    • 24-bit truecolor
    • pHYs + iCCP + cHRM
• XnView v1.99.6
  • Save As... = Export...
    • 4042 bytes
    • 8-bit greyscale
    • pHYs + iCCP + cHRM

Related post: Editing an images loses its transparency