Sets the bits of color data for a bitmap to the specified values
#include <WinAPIGdi.au3>
_WinAPI_SetBitmapBits ( $hBitmap, $iSize, $pBits )
| $hBitmap | Handle to the bitmap to be set. This must be a compatible bitmap (DDB). | 
| $iSize | The number of bytes pointed to by the $pBits parameter. | 
| $pBits | A pointer to an array of bytes that contain color data for the specified bitmap. | 
| Success: | the number of bytes used in setting the bitmap bits. | 
| Failure: | 0. | 
Search SetBitmapBits in MSDN Library.