SPG

### main function:function disp($pid) {      if (file_exists("pic-".$pid.".JPG")) {            echo "<img src=pic-".$pid.".JPG>";            echo "<br><br>";            if (file_exists("pic-".($pid-1).".JPG")) {                  echo "Previous &nbsp; ";            }            if (file_exists("pic-".($pid+1).".JPG")) {                  echo "Next";            }      } else {            echo "this file doesn't exist, try here";      }}### code for displaying:if ($_GET['pid']) {      disp($_GET['pid']);} else {      disp(1);}