How to spot differences in image quality?

Question

PHP

Greetings! I work with images, the same code on the local server and on the dev produces different image quality. Local - windows, dev - unix.
GD libraries are used. Quality is 100 everywhere.
What can influence this? Why different result after resize?

Answer 1

check the versions of gd, this is the first thing that comes, if you really don't like it - rewrite it on imageMagic, the quality seems to be better there. Also, try changing the default conversion settings, for example, to a bicubic (if not set). There, inside, there are a bunch of settings that are defined by default, but they affect the quality rather robustly.