PHP code displaying array of images from mysql database but unable to retrieve id -

i need id(primary key) of image clicked user code retrieve image while loop

            function displayimage()             {                 $con = mysqli_connect("localhost","root","programoften");                 mysqli_select_db($con,"tablename");                 $qry = "select * photos";                 $result = mysqli_query($con, $qry);                 while($row = mysqli_fetch_array($result))                 {                     echo '<img height="300 width="300" src="data:image;base64,'.$row[9].' ">';                     echo '<br />';                 }              } 

i'm not quite sure if code used display each image efficient code, here asking guys. thanks