function BMPtoJPG():boolean;
var Bitmap: TBitmap;
    JpegImg: TJpegImage;
begin
  Result:=False;
  Bitmap := TBitmap.Create;
  try
   Bitmap.LoadFromFile('C:\webcam.bmp') ;
   JpegImg := TJpegImage.Create;
   try
    JpegImg.Assign(Bitmap) ;
    JpegImg.SaveToFile('C:\webcam.jpg') ;
    Result:=True;
   finally
    JpegImg.Free
   end;
  finally
   Bitmap.Free
  end;