a Windows CMD batch to process images with https://github.com/tanakamura/waifu2x-converter-cpp.

waifu2x.bat

@echo off
pushd "%~dp0"
setlocal enabledelayedexpansion

if /i %PROCESSOR_ARCHITECTURE% == x86 set bin=waifu2x-converter_x86.exe
if /i %PROCESSOR_ARCHITECTURE% == amd64 set bin=waifu2x-converter_x64.exe

:LOOP
	set __test=%1
	
	if not defined __test goto END
	
	set i="%~dpnx1"
	set o="%~dpn1%_waifu2x.png"
	
	if not exist %i% goto CONTINUE
	
	echo Processing %~nx1...
				
	if /i %~x1 == .jpg set is_jpeg=1
	if /i %~x1 == .jpeg set is_jpeg=1
				
	if defined is_jpeg (
		%bin% -m noise_scale --noise_level 1 --scale_ratio 2 -i %i% -o %o% > NUL
	) else (
		%bin% -m scale --scale_ratio 2 -i %i% -o %o% > NUL
	)
		
	:CONTINUE
		
	shift
	goto LOOP
:END
	pause