#include <GDIPlus.au3>
$sImageFile = @DesktopDir & '\001.bmp'
$sExt = StringRegExpReplace($sImageFile, '^.*\.', '')
$sOutImageFile = StringRegExpReplace($sImageFile, '\.[^\.]*$', '')
_GDIPlus_Startup()
$hImage = _GDIPlus_ImageLoadFromFile($sImageFile)
$iX = _GDIPlus_ImageGetWidth($hImage)
$iY = _GDIPlus_ImageGetHeight($hImage)
$iXCloneSize = $iX / 4
$iXCropPos = 0
For $i = 1 To 4
; Create 32 bit bitmap clone
$hClone = _GDIPlus_BitmapCloneArea($hImage, $iXCropPos, 0, $iXCloneSize, $iY, $GDIP_PXF32RGB)
; Save bitmap to file
_GDIPlus_ImageSaveToFile($hClone, $sOutImageFile & '_' & $iXCropPos & '-' & ($iXCropPos + $iXCloneSize) & '.' & $sExt)
; Release resources
_WinAPI_DeleteObject($hClone)
$iXCropPos += $iXCloneSize
Next
; Release resources
_GDIPlus_ImageDispose($hImage)
_GDIPlus_Shutdown()