Image source not readable Laravel 5

I'm working with related tables and this time I can insert the image name in the database, but I am not able to save the image in the folder giving this error Image source not readable

Some help?

Controller

public function InserirPortfolio(Request $request) { 
    $portfolio = Input::except('_token'); 
    $portfolio['id'] = Input::get('id');
    $validation = Validator::make($portfolio, Portfolio::$portfolio); 
    if ($validation->passes()) {
        if($user = Portfolio::find($portfolio['id'])) {
            $user -> update($portfolio); 
            Session::flash('editarportfolio', 'Portfolio editado com sucesso'); 
            return Redirect::to('backend/portfolio');                   
        }else{
            $portfolio = new Portfolio();
            $portfolio->title= Input::get('title');
            $portfolio->year= Input::get('year');
            $portfolio->save();
            $image= new PortfolioImage();
            if($request->hasFile('image')){
                $file = array_get($portfolio,'image');
                $destinationPath = 'image/portfolio/';
                $extension =  $request->file('image')->getClientOriginalExtension();
                $fileName = rand(1111,9999) . '.' . $extension;
                $student->image = $fileName;
                Image::make($file)->resize(1000, 750)->save($destinationPath.$fileName);
            }
            $image->Portfolio()->associate($portfolio);
            $image->save();
        }
        Session::flash('portfolio', 'success'); 
        return Redirect::to('backend/portfolio');
    } else { 
        return Redirect::to('backend/portfolio/editar/'.$portfolio['id'])->withInput()->withErrors($validation); 
    }   
}           return Redirect::to('backend/portfolio');
    } else { 
        return Redirect::to('backend/portfolio/editar/'.$portfolio['id'])->withInput()->withErrors($validation); 
    }   
}

Relation

class Portfolio extends Model
{
    protected $table = 'portfolio';

    protected $fillable = ['id','title','year','description'];

    public function imageportfolio(){ 
        return $this->hasMany('App\ImagePortfolio','id_portfolio','id')->first(); 
    }

    public static $portfolio = array(
            'title' =>  'required',
            'year' =>  'required',
            'description' =>  'required',
            );      
}

class ImagePortfolio extends Model
{
    protected $table = 'imageportfolio';

    protected $fillable = ['id','id_portfolio','image'];

    public function portfolio() {
        return $this->belongsTo('App\Portfolio', 'id_portfolio');
    }

    public static $imageportfolio= array(
            'image' => 'image|max:3000|mimes:jpeg,jpg,png'
            );      
}

via Chebli Mohamed