We can extract the base64 image data from that string, decode it and save it to disk, don't need GD since it already is a png.
<?php // requires php5 define('UPLOAD_DIR', 'images/'); $img = $_POST['img']; $img = str_replace('data:image/png;base64,', '', $img); $img = str_replace(' ', '+', $img); $data = base64_decode($img); $file = UPLOAD_DIR . uniqid() . '.png'; $success = file_put_contents($file, $data); print $success ? $file : 'Unable to save the file.'; ?>