About PNG Quality Loss

This folder has before and after examples of the ways that shrinkpix 
1.1's results can be subpar for some PNGs.  

It's important to note that these are rare exceptions to the rule. 
In usage to date, most PNG and all JPEG results are indistinguishable 
from originals at normal viewing scale.  You should always inspect 
results and restore those you don't like, but restores are atypical.

Example: for the initially targeted site, images' shadow banding was
acceptable where it cropped up, but color loss and blurring warranted
restoring 3 PNG images - out of the hundreds (and perhaps thousands) 
of images shrunk acceptably.

It's also possible that this program's results will improve with
time.  As currently coded, though, shrinkpix's results for larger 
PNGs are wholly dependent on Pillow's default quantize method,
whose results have not varied from Pillow versions 4 through 7.  

Even so, in testing, most PNG image results were better with quantize 
than with decreased dimensions; quantize better retains the sharpness
of text and lines, which is especially important for screenshots.
Though it's your call to make, some shrinkpix subpar results may be
preferable to those produced by lowering dimensions in other tools.