How to implement "colorise" hue/saturation in game development.

Question

I am  a game developer,
recently the art desiginer give me lots of image ,whitch changed color use photoshop colorise hue/saturation from one garyscale image .
In order to reduce the image size. I have google for a lot time, I awalys do not konw the photoshop  "colorise" hue/saturation algorithm.
the common  hue/saturation change can use colormatrix ,
but how to  implement "colorise" hue/saturation in source code.

Answer 1

Thank You for the help.
As you said, I have change the color from garysacle to colorise.
Ignore the image quality that my code gen.
I have check my code many times,
but why the image center is Not (255,255,255).
this is My Source Code:
protected function onComplete(event:Event):void
                              var b:Bitmap=event.target.content;
                              this.addChild(b);
                              for (var i:int=0; i < b.width; i++)
                                        for (var j:int=0; j < b.height; j++)
                                                  var c:uint=b.bitmapData.getPixel32(i, j);
                                                  if (c != 0)
                                                            var a:int=((c >> 24) & 0xff);
                                                            var hsb:HSBColor=HSBColor.convertRGBtoHSB(c);
                                                            hsb.hue=0;
                                                            hsb.saturation=1;
                                                            b.bitmapData.setPixel32(i, j, HSBColor.convertHSBtoRGB(hsb.hue, hsb.saturation, hsb.brightness) + (a << 24));