405(方法不允许）在Laravel 5.2上路由文件路径时

在用户帐户更新请求中，UserController.php是：

    public function postSaveAccount(Request $request) {
            $this->validate($request, [
                'first_name' => 'required|max:120',
            ]);
            $user = Auth::user();
            $user->first_name = $request['first_name'];
            $user->update();
            $file = $request->file('image');
            //todo: treat image and upload other formats, maybe unique hash.
            $filename = $request['first_name'] . '-' . $user->id . '.jpg';
            if ($file) {
                Storage::disk('local')->put($filename, File::get($file));
            }
            return redirect()->route('account');
        }
    public function getUserImage($filename) {
        $file = Storage::disk('local')->get($filename);
        return new Response($file, 200);
     }

关于routes.php:

       Route::get('/account', [
          'uses' => 'UserController@getAccount',
          'as' => 'account',
          'middleware' => 'auth',
        ]);
        Route::post('/updateaccount', [
            'uses' => 'UserController@postSaveAccount',
            'as' => 'account.save',
            'middleware' => 'auth',
        ]);
        Route::post('/userimage/{filename}', [
            'uses' => 'UserController@getUserImage',
            'as' => 'account.image',
        ]);

在视图上：

@section('content')
    <section class="row new-post">
        <div class="col-md-6 col-md-offset-3">
            <header><h3>Your Account</h3></header>
            <form action="{{ route('account.save') }}" method="post" enctype="multipart/form-data">
                <div class="form-group">
                    <label for="first_name">First Name</label>
                    <input type="text" name="first_name" class="form-control" value="{{ $user->first_name }}" id="first_name">
                </div>
                <div class="form-group">
                    <label for="image">Image (only .jpg)</label>
                    <input type="file" name="image" class="form-control" id="image">
                </div>
                <button type="submit" class="btn btn-primary">Save Account</button>
                <input type="hidden" value="{{ Session::token() }}" name="_token">
            </form>
        </div>
    </section>
    @if (Storage::disk('local')->has($user->first_name . '-' . $user->id . '.jpg'))
        <section class="row new-post">
            <div class="col-md-6 col-md-offset-3">
                <img src="{{ route('account.image', ['filename' => $user->first_name . '-' . $user->id . '.jpg']) }}" alt="" class="img-responsive">
            </div>
        </section>
    @endif
@endsection

我得了405分（不允许使用方法）。文件上传正确，我使用的是正确的外观。只是url路由没有正确显示，有什么建议吗？

Tnks。