uses
  GdiPlus;

type
  TOpacity = 0..100;

procedure GDIPAlphaBlend(const FileName: string; Destination: TCanvas;
  const X, Y: Integer; const Opacity: TOpacity = 100);
var
  GPImage: IGPImage;
  GPGraphics: IGPGraphics;
  GPColorMatrix: TGPColorMatrix;
  GPImageAttributes: IGPImageAttributes;
begin
  GPImage := TGPImage.Create(FileName);

  GPColorMatrix.SetToIdentity;
  GPColorMatrix.M[3, 3] := Opacity / 100;
  GPImageAttributes := TGPImageAttributes.Create;
  GPImageAttributes.SetColorMatrix(GPColorMatrix);

  GPGraphics := TGPGraphics.Create(Destination.Handle);
  GPGraphics.DrawImage(GPImage, X, Y, GPImage.Width, GPImage.Height, 0, 0,
    GPImage.Width, GPImage.Height, UnitPixel, GPImageAttributes);
end;