Found IT!
argb=ReadPixelFast(x,y,ImageBuffer(image_name))
gotr=(ARGB Shr 16) And $ff
gotg=(ARGB Shr 8) And $ff
gotb=ARGB And $ff
GrayValue = (gotg+gotr+gotb) / 3
argb=ReadPixelFast(x,y,ImageBuffer(image_name))
gotr=(ARGB Shr 16) And $ff
gotg=(ARGB Shr 8) And $ff
gotb=ARGB And $ff
GrayValue = (gotg+gotr+gotb) / 3