passing base64string to php file using ajax and post - php

Question

Using mobile apllication here, I am sending image encoded data to php file using post method and getting the image url from the php file. The problem here is, I am not getting proper image while am sending string using ajax. When I place the image data manually, I am able to view the image, but when sending the image data using ajax call, unable to view the image.
<?php
//$image = $_POST['uploadedfile'];//not working if an ajax call is made what is the issue here
$image ="base64 string of an image here";//working if i place base 64 string here
$binary = base64_decode($image);
$fileName = time() . ".jpeg";
file_put_contents('images/' . $fileName, $binary);
if (file_exists('images/' . $fileName)) {
$myjson12 = "[";
$myjson12.='{';
$myjson12.='"Certificate":"http://domain/demo/images/'.$fileName.'"';
$myjson12.='}';
$myjson12.="]";
echo "$myjson12";
} else {
echo 'FAILURE';
}
?>
When I am accessing the file url and sending the parameter value the output is coming as url is too long: www.domain.com/getdata.php?uploadedfile=base64stringvalue;
here is my ajax call
$.ajax({
type: "POST",
url: "www.domain.com/getdata.php",
data: { "uploadedfile": c.toDataURL("image/jpeg") },
// dataType: "json",
success: function (response) {
console.log(response + "Sri");
$("#loadImg").hide();
alert("Success");
},
error: function (data) {
$("#loadImg").hide();
alert("Connection Failed");
}
});