set /a width = 128 * %1 / (100-%1)

set /a rwidth= 25600 / (100-%1)

:treeProcess

rem Do whatever you want here over the files of this subdir, for example:

for %%f in (*.jpg) do (

c:\imagemagick\convert "%%f"   -set option:distort:viewport "%%[fx:min(w,h)]x%%[fx:min(w,h)]+%%[fx:max((w-h)/2,0)]+%%[fx:max((h-w)/2,0)]" -filter point -distort SRT 0  +repage "%%f"

c:\imagemagick\convert.exe -resize %rwidth%x%rwidth% "%%f" "%%f"

c:\imagemagick\convert.exe -crop 256x256+%width%+%width% "%%f" "%%f"

)

for /D %%d in (*) do (

    cd %%d

    call :treeProcess

    cd ..

)

exit /b