function getImgDesc($imgName, $descDir){
  $arr = pathinfo($imgName);
  $descFileName = $arr['filename'] . ".txt";
  if(file_exists("$descDir/$descFileName")){
    $desc = file_get_contents("$descDir/$descFileName");
  }
  else{
    $desc = "brak opisu";
  }
  return $desc;
}