delphi显示 jpg、png、gif 图片及 gif 动画的方法

unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls;
type
TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses jpeg, GIFImg, pngimage;
{显示 jpg 图片}
procedure TForm1.Button1Click(Sender: TObject);
var
jpg: TJPEGImage;
begin
jpg := TJPEGImage.Create;
jpg.LoadfromFile('C:\Temp\Test.jpg');
Canvas.Draw(0, 0, jpg);
jpg.Free;
end;
{显示 png 图片}
procedure TForm1.Button2Click(Sender: TObject);
var
png: TPngImage;
begin
png := TPngImage.Create;
png.LoadfromFile('C:\Temp\Test.png');
Canvas.Draw(0, 0, png);
png.Free;
end;
{显示 gif 图片}
procedure TForm1.Button3Click(Sender: TObject);
var
gif: TGIFImage;
begin
gif := TGIFImage.Create;
gif.LoadfromFile('C:\Temp\Test.gif');
Canvas.Draw(0, 0, gif);
gif.Free;
end;
{显示 gif 动画}
procedure TForm1.Button4Click(Sender: TObject);
var
gif: TGIFImage;
begin
gif := TGIFImage.Create;
gif.LoadfromFile('C:\Temp\Test.gif');
gif.Animate := True;
with TImage.Create(Self) do begin
    Parent := Self;
    Left := 0;
    Top := 0;
    Picture.Assign(gif);
end;
gif.Free;
end;
end.