On 17/02/2020 21:23, Big Al wrote:
optipng doesn't change the image quality any?Â*Â* I've never used it, just
installed it on my system.Â* I ran a test and some images were cut in
half.Â* My eye doesn't see any quality diff.

Further to my first reply. "Cut in half" is rare and suggests that the
original program that created them didn't choose the compression
parameters at all well, or maybe chose them aiming for highest possible
execution speed, or tested only on a photo where the more intensive
compression often makes only a little difference.

--
Brian Gregory (in England).