You're missing out a step. Even though you have one row, you still need to fetch the result, not just link to the query. So something like this:
PHP Code:
function get_image($image_id){
//finds and displays the selected image
global $connection;
$query = "SELECT *
FROM tbl_picture_link
where picture_link_id = {$image_id}
LIMIT 1";
//get query result
$query_result = mysql_query($query, $connection);
//fetch result as an array
$picture_set = mysql_fetch_array($query_result);
confirm_query($picture_set);
echo "<img scr=\"" . $picture_set['picture_link_href'] . "\">" . $query."<br />";
}
Note as you only have one row returned, you only call the mysql_fetch_array once. If you wanted to do more than one row, you need to do a while loop or something to keep calling mysql_fetch_array and get the new rows.