Night - Day Filter

Okay I don't get how it all works togeather can you rewrite the code to use the Red, Blue, Green thing
NeverMind thanks it worked :P

is there way to make 0 full bright and 1 full darkness in my code..??

Function FB_DarkenImage ( image, d#=1 )

	For ix = 0 To ImageWidth( image ) - 1
		For iy = 0 To ImageHeight( image ) - 1
			Local rbgc = ReadPixel( ix, iy, ImageBuffer(image) )
			Alpha% = (rbgc And $FF000000) Shr 24 
			Red% = (rbgc And $00FF0000) Shr 16 
			Green% = (rbgc And $0000FF00) Shr 8 
			Blue% = rbgc And $000000FF
			Red = Red * d#
			Green = Green * d#
			Blue = Blue * d#
			rbgc = (Alpha Shl 24) + (Red Shl 16) + (Green Shl 8) + Blue 
			If rbgc = $FFFF00FF
				WritePixel ix,iy,($0),ImageBuffer(image)		
			Else
				WritePixel ix,iy,(rbgc), ImageBuffer(image)
			EndIf
		Next
	Next
	
	Return image

End Function 

[edit]
How would I also lighten that image using this code basicly im trying to make a code depending on % the images brightness will be changed :) can you see what needs to be added