Save an image in camanjs

Good afternoon,

I'm using the camanjs plugin and I'm not able to save the image to the server, I have the code like this:

<img id="camanimage" src="image.jpg" style="height:200px;">

No javascript:

Caman("#camanimage", function () {  
  this.brightness(10);
  this.contrast(10);

  this.render(function(){

    //this.save(); Funciona

    var imagedata = this.toBase64();

solution: this line was missing to remove the initial part of the data image:

    var raw_image_data = imagedata.replace(/^data\:image\/\w+\;base64\,/, '');


    $.post("salvafoto.php", { imagedata: raw_image_data },
      function(info){
      }
    );
// ... 

Then in salvafoto.php I have this:

$encodedData = base64_decode($_POST['imagedata']);
$result = file_put_contents( 'teste.jpg', $encodedData );

When you open the image, it is always black with an error. Does anyone know why? If you use this.save() it downloads but it works.