Convert png/jpg/gif to ico

Question

I have multiple images some of them are png some of them jpg and gif and i want to display them in a listview as thumbails TImageList supports only icons how can i convert them to be able to insert them in TImageList.

I am using Delphi XE

Answer 1

To specifically answer the question, also to take simple resizing into account (for thumbnails), some example code:

var
  Img: TImage;
  BmImg: TBitmap;
  Bmp: TBitmap;
  BmpMask: TBitmap;
  IconInfo: TIconInfo;
  Ico: TIcon;
begin
  Img := TImage.Create(nil);
  Img.Picture.LoadFromFile(...

  BmImg := TBitmap.Create;
  BmImg.Assign(Img.Picture.Graphic);
  Img.Free;

  Bmp := TBitmap.Create;
  Bmp.SetSize(ImageList1.Width, ImageList1.Height);
  SetStretchBltMode(Bmp.Canvas.Handle, HALFTONE);
  StretchBlt(Bmp.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height,
              BmImg.Canvas.Handle, 0, 0, BmImg.Width, BmImg.Height, SRCCOPY);
  BmImg.Free;

  BmpMask := TBitmap.Create;
  BmpMask.Canvas.Brush.Color := clBlack;
  BmpMask.SetSize(Bmp.Width, Bmp.Height);

  FillChar(IconInfo, SizeOf(IconInfo), 0);
  IconInfo.fIcon := True;
  IconInfo.hbmMask := BmpMask.Handle;
  IconInfo.hbmColor := Bmp.Handle;

  Ico := TIcon.Create;
  Ico.Handle := CreateIconIndirect(IconInfo);

  ImageList1.AddIcon(Ico);

  Bmp.Free;
  BmpMask.Free;
  Ico.Free;  // calls DestroyIcon
end;

or, without creating an icon:

var
  Img: TImage;
  BmImg: TBitmap;
  Bmp: TBitmap;
begin
  Img := TImage.Create(nil);
  Img.Picture.LoadFromFile(..

  BmImg := TBitmap.Create;
  BmImg.Assign(Img.Picture.Graphic);
  Img.Free;

  Bmp := TBitmap.Create;
  Bmp.SetSize(ImageList1.Width, ImageList1.Height);
  SetStretchBltMode(Bmp.Canvas.Handle, HALFTONE);
  StretchBlt(Bmp.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height,
              BmImg.Canvas.Handle, 0, 0, BmImg.Width, BmImg.Height, SRCCOPY);
  BmImg.Free;

  ImageList1.AddMasked(Bmp, clNone);

  Bmp.Free;
end;