<a href="www.mysite.com/showimage.php?id=1">Show image 1</a>

<?php
$imageid = $_GET['id'];

$servername = ...;
$username = ...;
$password = ...;
$dbname = ...;

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("Connection to MySQL failed: " . $conn->connect_error);
}

htmlspecialchars($imageid);
stripslashes($imageid);
mysqli_real_escape_string($conn, $imageid);


$sql = "SELECT * FROM images WHERE id = '$imageid'";
$result = $conn->query($sql);


if (is_object($result) && $result->num_rows > 0) {

            while($row = $result->fetch_assoc())
            {
                // Replace "image, image_name ecc." with the columns of the table
                echo $row["image"];
                echo "Name: " . $row["image_name"];
                echo "Info: " . $row["image_useful_info"];
                echo "Price: " . $row["image_price"];
        }
            $conn->close();
            die();
        }
        else
            echo "The image you requested was not found.";
?>