@echo off
rem https://www.imagemagick.org
setlocal enableextensions enabledelayedexpansion

set convert=c:\Programs\ImageMagick-7.0.6-0\convert.exe
set magic=c:\Programs\ImageMagick-7.0.6-0\magick.exe

for /f "tokens=*" %%a in ('dir *.jpg /b') do ( call :main %%a )

goto :EOF

:main
setlocal enableextensions enabledelayedexpansion
for /f "tokens=1,2 delims= " %%i in ('%magic% identify -format "%%w %%h" %~f1') do (
    set w=%%~i
    set h=%%~j
)
if !w! GTR !h! (
    set hc=10
    set /a wc=!w!/2
) else (
    set /a hc=!h!/2
    set wc=10
)
if !w! GTR !h! (set min=!h!) else (set min=!w!)
set /a h2=!h!/2
set /a w2=!w!/2
%convert% -size !w!x!h! xc:PeachPuff -fill LightBlue -draw "circle !w2!,!h2! !wc!,!hc!" -transparent LightBlue mask.png
%convert% %~f1 mask.png -composite temp.png
%convert% temp.png -transparent PeachPuff temp.png
%convert% temp.png -gravity Center -crop !min!x!min!+0 %~dpn1.png
del mask.png temp.png