Getting record at random from database

[cafeenman]

I haven't been able to figure this one out. On my photography page, I want to display an image at random whenever someone goes to the page. It would probably be best if the image didn't change when they refresh the page, but I haven't even looked at sessions yet, so really I just want to know how to select a random record.

http://www.paulkjohnson.com/photography/

<?PHP

$db = @mysql_connect(etc);
mysql_select_db('Photography');

if ($ImageID > 0)
    {
        $query = mysql_query("SELECT Subject,Filename,Year,Caption FROM photographs WHERE ImageID = '$ImageID'");
        $BasePath = 'images/';
        $Caption = mysql_result($query,0,"Caption");
        $Filename = mysql_result($query,0,"Filename");
        $FullPath = "$BasePath$Filename";
        echo "<p align=\"center\"><img src=$FullPath></p>";

        echo "<p align=\"center\">$Caption</p>";

        $Copyright = "Copyright © ";
        $Year =mysql_result($query,0,"Year");
        $Author = " Paul K. Johnson";
        echo "<p align=\"center\">$Copyright$Year$Author</p>";
        $query = mysql_query("update photographs set Count = Count +1 where ImageID='$ImageID'");
    }
else // display a random image
    {
      $query = mysql_query("SELECT * FROM photographs");
                // pick one at random
    }
?>

I know how to display it so all I need is the next line of code.