decode base64 image on php get blank image - php

Question

I'm trying to decode base64 image on php but i get blank image with black screen showing that windows doesn't support this type of file.
Here is my code
public function uploadfoto(){
$img = $_POST['foto'];
$img = str_replace('data:image/jpeg;base64,', '', $img);
$img = str_replace(' ', '+', $img);
$data = base64_decode($img);
$filedir = "./assets/upload/presensi/mx_" . mktime() . ".jpg";
$filename = "mx_".mktime().".jpg";
$result = file_put_contents($filedir, $data);
}
I get the image from my webcam and here is my view
<form id ="inputfoto">
<div id="my_camera" style="width: 320px; height: 240px;" class="center"></div>
<!-- First, include the Webcam.js JavaScript Library -->
<script type="text/javascript" src="<?php echo base_url();?>assets/dist/js/webcamjs/webcam.js"></script>
<!-- Configure a few settings and attach camera -->
<script language="JavaScript">
Webcam.set({
width: 320,
height: 240,
image_format: 'jpeg',
jpeg_quality: 100
});
Webcam.attach( '#my_camera' );
</script>
<div id="results" align = "middle" >Hasil akan tampil di sini</div>
<input type="button" value="Take Snapshot" onclick="take_snapshot()" class="center" style="margin-bottom: 5px;">
<input type="button" value="Submit" onClick="saveSnap()" class="center">
</form>
<script language="JavaScript">
function take_snapshot() {
// take snapshot and get image data
Webcam.snap( function(data_uri) {
// display results in page
document.getElementById('results').innerHTML =
'<h2>HASIL</h2>' +
'<img id="foto" src="'+data_uri+'"/>';
} );
}
function saveSnap(){
var file = document.getElementById("foto").src;
var formdata = new FormData();
formdata.append("foto", file);
var ajax = new XMLHttpRequest();
ajax.open("POST", "<?php echo base_url();?>asisten/presensi/uploadfoto");
ajax.send(formdata);
}
</script>
And here is the
Blank Image
What's wrong with my code? Thank you very much for your respond.

Answer 1

This code works for me.Please check it
$image = $this->generateImage($_POST['foto']);
public function generateImage($img)
{
$folderPath = "uploads/";
$image_parts = explode(";base64,", $img);
$image_type_aux = explode("uploads/", $image_parts[0]);
$image_base64 = base64_decode($image_parts[1]);
$name = uniqid() . '.png';
$file = $folderPath . $name;
file_put_contents($file, $image_base64);
return $name;
}