<script type="text/javascript">

    $("#save_user_profile").click(function (event) {
        event.preventDefault();
        var authorizationToken = $("#authtoken").val();
        var form = document.forms.namedItem("user_profile_form"); // high importance!, here you need change "yourformname" with
        var formData = new FormData(form);


        $.ajax({
            headers: {
                'Authorization': authorizationToken,
                'device_type': 'android'
            },
            async: true,
            type: 'post',
            contentType: false,
            cache: false,

            url: '{{ action('MobileUserProfileController@updateUserProfile') }}',
            data: formData,
            processData: false,
            success: function (data) {
                var result = JSON.parse(data);

                if (result.status) {
                    alert(result.message);
                } else {
                    alert(result.message);
                }
            },
            error: function (jqXHR, textStatus, errorThrown) {
                alert(errorThrown);
            }
        });
    });


    Android.pageParams("Profile", "", "", false, "", "", "");
</script>

public function updateUserProfile(Request $request)
    {

        $userimg = $request->file('user_profile_picture');
        echo json_encode(['status' => true, 'message' => $_FILES]);
    }

{"status":true,"message":{"user_profile_picture":{"name":"","type":"","tmp_name":"","error":4,"size":0}}}

$userimg = $request->file('user_profile_picture');
echo json_encode(['status' => true, 'message' => $userimg]);