unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ExtCtrls, Vcl.Imaging.pngimage;

type
  TForm1 = class(TForm)
    Image1: TImage;
    procedure FormCreate(Sender: TObject);
    procedure ImageMouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure ImageMouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
    procedure ImageMouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  img1, img2: Timage;
  StartCoord: TPoint;
  Move: Boolean;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
   img1 := TImage.Create(self);
   img1.Parent := Form1;
   img1.Picture.LoadFromFile('G:\Downloads\bb.png');
   img1.OnMouseDown := ImageMouseDown;
   img1.OnMouseMove := ImageMouseMove;
   img1.OnMouseUp := ImageMouseUp;
   img1.Stretch := True;
end;

procedure TForm1.ImageMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
   with Sender as TImage do
   begin
      if Move then
      begin
         if X > StartCoord.X then
            Image1.Left := Image1.Left + (X - StartCoord.X);
         if X < StartCoord.X then
            Image1.Left := Image1.Left - (StartCoord.X - X);
         if Y > StartCoord.Y then
            Image1.Top := Image1.Top + (Y - StartCoord.Y);
         if Y < StartCoord.Y then
            Image1.Top := Image1.Top  - (StartCoord.Y - Y);
      end;
   end;
end;

procedure TForm1.ImageMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
    with sender as TImage do
      Move := False;
end;

procedure TForm1.ImageMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
    with sender as TImage do
    begin
   Move := True;
   StartCoord.X := X;
   StartCoord.Y := Y;
    end;
end;

end.