How to load an 'open' picture into a TImage without opening a file twice

During run time several JPGs, or GIFs, need to be diplayed. However, the size of these images differs greatly and therefore I use two TImages, e.g.: ImGIF and ImGIFsmall, each on their own TPanel. Based on the actual size of the loaded image the code will use ImGIF or ImGIFsmall. The code that I am using is this:

var
  pict      : TPicture;
  F_Small   : boolean;
  FName     : string;
begin
  F_Small := false;
  pict := TPicture.Create;
  try
    pict.LoadFromFile(FName);      // 1st load
    if (pict.Width < 400) AND (Pict.Height < 400) then F_Small := true;
  finally
    pict.Free;
  end;
  if not F_Small then begin        // big GIF - use big TIMage
      Try
        if FileExists(FName) then begin
          With Form1 do begin
            imGIF.Picture.LoadFromFile(FName);   // 2nd load
            (imGIF.Picture.Graphic as TGIFImage).Animate := true;
            pnlGif.Visible := true;
            imGIF.Visible := true;
            pnlGifsmall.Visible := false;
            imGIFsmall.Visible := false;
          end;
        end;
      Except
        .. // error message
      End;
    end else begin                 // small GIF - use small TIMage
      ... // same for imGIFsmall
    end;
end;

As you see, I am accessing the *.GIF file on disk twice, probably costing unnecessary run time. I didn't find a way to use the open Tpicture (required for getting its size) and put that into the TImage. All my search results come back with the LoadFromFile() method.

Solution

You can simply Assign() the opened TPicture to the desired TImage.Picture before freeing it, eg:

var
  pict: TPicture;
  img: TImage;
  F_Small: Boolean;  
  ...
begin
  ...

  pict := TPicture.Create;
  try
    pict.LoadFromFile(...);
    F_Small := (pict.Width < 400) and (Pict.Height < 400);
    if F_Small then
      img := Form1.imGIFsmall
    else
      img := Form1.imGIF;
    img.Picture.Assign(pict);
  finally
    pict.Free;
  end;

  if img.Picture.Graphic is TGIFImage then           
    TGIFImage(img.Picture.Graphic).Animate := True;

  Form1.pnlGif.Visible := not F_Small;
  Form1.imGIF.Visible := not F_Small;
  Form1.pnlGifsmall.Visible := F_Small;
  Form1.imGIFsmall.Visible := F_Small;

  ...
end;