procedure 
TForm2.Button2Click(Sender: TObject);
var FileName: string;response: string;
var formData: TIdMultiPartFormDataStream;
begin
FileName := 'c:\pic.gif';
formData := TIdMultiPartFormDataStream.Create;
formData.AddFile('File',fileName,'application/octet-stream');
formData.AddFormField('param1', 'value1');
//HttpObject.Port := Port;
response := idHTTP1.Post('http://myhost/ppost.php',formData);
Label1.Caption:= response ;
Memo1.Lines.Text:= response ;
end;