Serialization of 'Symfony\Component\HttpFoundation\File\UploadedFile' is not allowed

I'm not sure what this error is for since I have been using this throughout my entire site and it works fine in those areas. This is my model:

<?php namespace Duplicolor\Models\User;

use \Illuminate\Auth\UserTrait;
use \Illuminate\Auth\UserInterface;
use \Illuminate\Auth\Reminders\RemindableTrait;
use \Illuminate\Auth\Reminders\RemindableInterface;
use \Input;
use \Auth;
use \Config;
use \Intellectproductions\Verify\Verify;
use \Zizaco\Entrust\HasRole;
use \Laracasts\Presenter\PresentableTrait;
use \Duplicolor\Traits\ApprovalTrait;
use \Duplicolor\Traits\BaseTrait;
use \Duplicolor\Helpers\Uploader;
use \Session;

class User extends Verify implements UserInterface, RemindableInterface {

    use UserTrait, RemindableTrait, HasRole, PresentableTrait, ApprovalTrait, BaseTrait;

    public static $rules = array(
        'username'              => 'sometimes|required|max:50|unique:users,username',
        'email'                 => 'sometimes|required|email|max:50|unique:users,email',
        'password'              => 'sometimes|required|confirmed',
        'password_confirmation' => 'sometimes|required',
        'first_name'            => 'sometimes|required|max:45',
        'last_name'             => 'sometimes|required|max:45',
        'street'                => 'max:100',
        'city'                  => 'sometimes|required|max:45',
        'state'                 => 'max:2',
        'zip'                   => 'max:7',
        'country'               => 'max:50',
        'rules'                 => 'sometimes|required|accepted',
        'show_name'             => 'boolean',
        'avatar'                => 'image',
        'banner'                => 'image'
    );

    protected $fillable = array('first_name', 'last_name', 'street', 'city', 'state', 'zip', 'country', 'rules', 'signup', 'show_name');

    protected $presenter = '\Duplicolor\Presenters\User\UserPresenter';

    protected $identify = array('email', 'username'); // identify column in the db
    protected static $directory; // User avatar directory
    protected static $bannerDirectory; // User banner directory

    protected static $avatarWidth = 124;
    protected static $avatarHeight = 124;

    protected static $bannerWidth = 1024;
    protected static $bannerHeight = 338;

    function __construct($attributes = array()) {
        parent::__construct($attributes);

        $this->purgeFilters[] = function($key) {
            $purge = array('rules', 'signup');
            return ! in_array($key, $purge);
        };

        $this->approvalColumn = 'confirmed';
        self::$directory = Config::get('app.url') . Config::get('app.userPath');
        self::$bannerDirectory = Config::get('app.url') . Config::get('app.userBannerPath');
    }

    public static function boot()
    {
        parent::boot();

        User::saving(function($user)
        {
            // Check to see if they are changing their avatar
            if( ! is_null(Session::get('avatar')) )
            {
                // Upload image and get filename
                $uploader = new Uploader();
                $uploader->setDirectory(static::$directory);
                if( ! $uploader->uploadImage( Session::get('avatar'), array(static::$avatarWidth, static::$avatarHeight) ) )
                {
                    return false;
                }

                $this->avatar = $uploader->getRecentFile();
            }

            // Check to see if they are changing their banner
            if( ! is_null(Session::get('banner')) )
            {
                // Upload image and get filename
                $uploader = new Uploader();
                $uploader->setDirectory(static::$bannerDirectory);
                if( ! $uploader->uploadImage( Session::get('banner'), array(static::$bannerWidth, static::$bannerHeight) ) )
                {
                    return false;
                }

                $this->banner = $uploader->getRecentFile();
            }
        });
    }
}

My Uploader class looks like this:

<?php namespace Duplicolor\Helpers;

/**
 * Uploader Class
 * 
 * All methods related to handling files and using the Resizer object
 *
 * @author Haley Schillig <http://intellectproductions.com/>
 * @version 1.0
 * 
 */

use \Auth;
use \File;
use \Imager;

class Uploader {

    protected $directory; // Directory for images
    protected $recentFileUpload; // Recent file upload
    protected $width; // Width of image if resized
    protected $height; // Height of image if resized

    public function setDirectory( $value )
    {
        $this->directory = $value;
    }

    public function getRecentFile()
    {
        return $this->recentFileUpload;
    }

    /**
     * Upload images
     * @param image         Image object
     * @param resizeArgs    Width and height of image
     *
     */
    public function uploadImage( $image, array $resizeArgs = array() )
    {
          $fileName = $this->generateFileName( $image );

        $image->move($this->directory, $fileName);

            // now resize and upload
            if(count($resizeArgs) > 0)
            {
                // Set width and height
                $this->width = $resizeArgs[0];
                $this->height = $resizeArgs[1];

                // Resize image
                $this->resize($this->directory . $fileName);
            }

            $this->recentFileUpload = $fileName;

            return true;
    }
}

I didn't show the entire class because the error is specifically being thrown at this line:

$image->move($this->directory, $fileName);

I did a dd on the $image and it is returning the image object when the form is set to files => true so that's coming back fine. $this->directory holds the correct directory and $fileName holds the right value that was expected.

This is how I'm executing it all:

/**
 * Edit banner of user
 *
 */
public function postEditBanner()
{
    $user = $this->user->getById( Auth::id() );
    Session::put('banner', Input::file('graphic'));

    if( ! $user->updateUniques() )
    {
        return Redirect::to(URL::previous())
            ->withInput(Input::except('graphic'))
            ->withErrors( $user->errors()->all() );
    }

    return Redirect::to(URL::previous())
        ->withInput(Input::except('graphic'))
        ->with('success', 'Your banner was changed successfully');
}

Thanks if anyone can see anything blaringly wrong..