dataurl to image for download in php

Question

I'm creating image using canvas and using following script,

function getImage() {
    var canvas1 = document.getElementById("images");

    if (canvas1.getContext) {
        var ctx = canvas1.getContext("2d");
        var myImage = canvas1.toDataURL("image/jpg");
    }
    $('<form action="download.php" method="POST">' + 
    '<input type="hidden" name="aid" value="' + myImage + '">' +
    '</form>').submit();

}

And in my Download.php file is,

<?php $img = $_POST['aid']; 
    echo "<img src=".$img.">";
?>

it showing image correctly. But i wanna give download button with jpg format or pdf format.

How i can use?

I used base64_decode(); method. But i cant solve.

Help me...

Answer 1

Thanks for all. but I got answer using,

file_put_contents();

But thing, i dont know how to use. Finally i got it from this Answer.

Answer is,

$data = 'data:image/png;base64,AAAFBfj42Pj4';

list($type, $data) = explode(';', $data);
list(, $data)      = explode(',', $data);
$data = base64_decode($data);

file_put_contents('/tmp/image.png', $data);

But still i'm waiting for download button with option of image/pdf format.