How can I send files using TClientSocket & TServerSocket?
Sending files with TClientSocket/TServerSocket

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ScktComp, ExtCtrls, StdCtrls;

type
  TForm1 = class(TForm)
    Image1: TImage;
    Image2: TImage;
    ClientSocket1: TClientSocket;
    ServerSocket1: TServerSocket;
    Button1: TButton;
    procedure Image1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure ClientSocket1Connect(Sender: TObject;
      Socket: TCustomWinSocket);
    procedure ServerSocket1ClientRead(Sender: TObject;
      Socket: TCustomWinSocket);
    procedure ClientSocket1Read(Sender: TObject; Socket: TCustomWinSocket);
  private
    { Private declarations }
    Reciving: boolean;
    DataSize: integer;
    Data: TMemoryStream;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Image1Click(Sender: TObject);
begin
  // This is the procedure to open the socket for RECEIVING.
  // Button1.Click is this procedure as well.
  ClientSocket1.Active:= true;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  // Open the SENDING socket.
  ServerSocket1.Active:= true;
end;

procedure TForm1.ClientSocket1Connect(Sender: TObject;
  Socket: TCustomWinSocket);
begin
  // Send command to start the file sending.
  Socket.SendText('send');
end;

procedure TForm1.ClientSocket1Read(Sender: TObject;
  Socket: TCustomWinSocket);
var
  s, sl: string;
begin
  s:= Socket.ReceiveText;
  // If we're not in recieve mode:
  if not Reciving then
  begin
    // Now we need to get the length of the data stream.
    SetLength(sl, StrLen(PChar(s))+1); // +1 for the null terminator
    StrLCopy(@sl[1], PChar(s), Length(sl)-1);
    DataSize:= StrToInt(sl);
    Data:= TMemoryStream.Create;
    // Delete the size information from the data.
    Delete(s, 1, Length(sl));
    Reciving:= true;
  end;
  // Store the data to the file, until we've received all the data.
  try
    Data.Write(s[1], length(s));
    if Data.Size = DataSize then
    begin
      Data.Position:= 0;
      Image2.Picture.Bitmap.LoadFromStream(Data);
      Data.Free;
      Reciving:= false;
      Socket.Close;
    end;
  except
    Data.Free;
  end;
end;

procedure TForm1.ServerSocket1ClientRead(Sender: TObject;
  Socket: TCustomWinSocket);
var
  ms: TMemoryStream;
begin
  // The client wants us to send the file.
  if Socket.ReceiveText = 'send' then
  begin
    ms:= TMemoryStream.Create;
    try
      // Get the data to send.
      Image1.Picture.Bitmap.SaveToStream(ms);
      ms.Position:= 0;
      // Add the length of the data, so the client
      // will know how much data to expect.
      // Append #0 so it can determine where the size info stops.
      Socket.SendText(IntToStr(ms.Size) + #0);
      // Send it (the socket owns the stream from now on).
      Socket.SendStream(ms);
    except
      // So only free the stream if something goes wrong.
      ms.Free;
    end;
  end;
end;

end.