Description:
============
Hello boys. This scripts are written by fans to optimize .png mod files in great game FACTORIO!
Filesize of .PNG images will reduced UP TO 80%!!! It's not a joke or magic - it's technology!
Ofc so much reduce of filesize is unreal without some of careful lossy compression! BUT! You will not seen any differences between original and optimized images!!! If you'll chose the right script ofc ;)


How to use this sh...  shiny magic:
===================================
Drag and drop some .PNG files (up to 50-60 or so) on a one of .bat files named "DRAG..."

There are TWO .BAT scripts named:

#1) 1-DRAG PNG here (best compression for non-full-gradient and small files).bat
#2) 2-DRAG PNG here (good compression for gradient and truecolor pictures).bat

--> First script BEST USED FOR ordinary not so wide-colorful game graphics like rusty buildings, tilesets of the same units or types of ground, pixelart graphics, ingame icons and etc... because this script is used some more intensive optimizations and leaves only need colors and brings the best compression results you're ever seen!
--> Second script is BEST FOR images and sprites containing full-gradient on whatever flat surfaces, this script is mostly accurate and carefully delicate to colours, especially to their amount of quantity. Script is having excerpt of 256 of tones so you must dont see the borderlines in gradients of final image. Seems like almost lossless.. But this is less effective compression.

So if you don't know for now, you can simply make 2 copies of the same png and try to use each of script and get two different compressed files. Look at them and if you don't see the difference - take one with smallest size. Or with the best quality, if you see that. 
I leave exactly two scripts here, because first brings not so smooth gradients and second compress other files not so effective how it must be. So you're learn this soon if you'll practice with this scripts... or maybe you're will write later a new one for us? ;)

Comparsion:
===========

ordinary 2048x2048.png (64 sprites of factorio train from mods) = 3017Kb
lossless supercompress (not in this scripts) = 2694Kb - it's ~10,5% lighter... not impressive at all. :-/
our .BAT script #2 = 860 Kb! Wow... it's 71,5% lighter! Amazing...
our .BAT script #1 = 580 Kb!!! WOOOOOWw.. it's... __80,7%__!!! lighter... it's a SHOCK!!
- dude... but.. 0_O is it rrreal?
- Yes!
- Minus 80% filesize without JPEG?
- YES!!!
- But.. can anyone see visible artifacts or diversity distortion in images after this MAD compression?
- NOPE!
- It's a magic anyway, dude! I can't believe it!

Warning tips:
=============
- This scripts will REWRITE original files with optimized ones in their folders you'll drag them from! So backup originals before optimizing, if you need so.
- Because quality of image is important for us: script #1 is tuned so, that if quality loss of optimized image becoming big then program will STOP! And original png image will be NOT CHANGED! In this way you need to compress this png with script #2.
- Each of this two scripts is of full value and bring to png file all that needs in one run. So Don't use this two scripts one by one or twise or more on same files. This WILL affect minor quality loss of file and almost none of reducing filesize.
- Don't touch files in this folder if you don't know what you're doing
- The scripts and programs-optimizators here are one-threaded so you can drop groups of png in series before first files are end of optimizing. This will run parallel copies of programs that do not interfere with each other. Multicore CPU will love it. Your time will love that too.
- If you are paranoic of optimizations , you can change -s4 in scripts for -s5 ang get extreme level of compression from pingo module. Average reduce of size is 995Kb from 1Mb file and double time to wait. If you are want to reduce filesize again and again and more than any insane freak, then download FileOptimizer utility and you can reduce size of your already optimized png's a bit more further.
 
Credits and Thanks
==================
are going to creators one of the best (imho) png optimizators - pingo and pngquant!
 THANK YOU! All our PNGs are now shining!
homepage of pngquant: https://pngquant.org (ver. 2.8.1 used at scripts here)
homepage of pingo: http://css-ig.net/pingo (ver. 0.73 used at scripts here)

And to the creators of great game FACTORIO that teach me to be optimized ;)
homepage: https://www.factorio.com - go play this amazing game!!! Now with optimized images! :)

And to the creators of AWESOME mods for this game - all of you guys! You made our days everyday! 
And inspiring others to create great things! So if you a bit boring playing Factorio - try Bob's mods, and Yuoki mods and Angel's creations and many many more modmakers...

no credits for me... ;) Cheers! ^^)