<?php
header('Content-type: image/jpeg');

$mysql_host = 'localhost';
$mysql_user = 'example_user';
$mysql_pass = 'Kolosnjaj4321!';
$mysql_db = 'example_database';
$con = mysqli_connect($mysql_host, $mysql_user, $mysql_pass);
mysqli_select_db($con, $mysql_db);

if (isset($_GET['id'])) {
    $id = $_GET['id'];

    $query = mysqli_query($con, "SELECT `email` FROM `users` WHERE `id` ='" . mysqli_real_escape_string($con, $id) . "'");
    if (mysqli_num_rows($query) >= 1) {
        $query_result = mysqli_fetch_assoc($query);
        $email = $query_result['email'];
    } else {
        $email = 'ID not found';
    }
} else {
    $email = 'No id specified.';
}
$email_length = strlen($email);

$font_size = 4;

$image_height = imagefontheight($font_size);
$image_width = imagefontwidth($font_size) * $email_length;

$image = imagecreate($image_width, $image_height); // Stvaranje prazne slike

imagecolorallocate($image, 255, 255, 255); // boja pozadine podesena na belo
$font_color = imagecolorallocate($image, 0, 0, 0); // boja fonta podesena na belo

imagestring($image, $font_size, 0, 0, $email, $font_color);
imagejpeg($image);