How to update image using controller in laravel?

I want to update user image but it's not getting updated. I have used following controller for updating the image.. Can you suggest what's the mistake in controller function?

View part :

<div class="form-group">
            <label>Image Upload</label>
            <input type="file" name="image"  id="image"><img src="" width="200px"/></br>
 </div> 

Controller function :

public function update(Request $request, $id)
{
    $data=Course::findOrFail($id);  

    if ($request->hasFile('image'))
        {
            $file = $request->file('image');
            $timestamp = str_replace([' ', ':'], '-', Carbon::now()->toDateTimeString()); 
            $name = $timestamp. '-' .$file->getClientOriginalName();
            $data->image = $name;
            $file->move(public_path().'/images/', $name);              
        }   
          $data->update($request->all());              
      return redirect('course');
}

via Chebli Mohamed