undefined method `each' for nil:NilClassのエラー

undefined method `each' for nil:NilClassgaが解決できない

画像投稿アプリを作成しております。
index画面に投稿一覧を表示する機能を実装後に以下のエラーメッセージが発生しました。

NoMethodError in Posts#index

undefined method `each' for nil:NilClass

  <% @posts.each do |post| %>
    <div class="col-md-8 col-md-2 mx-auto">
      <div class="card-wrap">
        <div class="card">
          <div class="card-header align-items-center d-flex">

該当のソースコード

index.html.erb
 <% @posts.each do |post| %>
    <div class="col-md-8 col-md-2 mx-auto">
      <div class="card-wrap">
        <div class="card">
          <div class="card-header align-items-center d-flex">
            <%= link_to user_path(post.user), class: "no-text-decoration" do %>
              <%= image_tag avatar_url(post.user), class: "post-profile-icon" %>
            <% end %>
            <%= link_to user_path(post.user), class: "black-color no-text-decoration",
              title: post.user.name do %>
              <strong><%= post.user.name %></strong>
            <% end %>

            <% if post.user_id == current_user.id %>
              <%= link_to post_path(post), method: :delete, class: "ml-auto mx-0 my-auto" do %>
                <div class="delete-post-icon">
                </div>
              <% end %>
            <% end %>

          </div>

          <%= link_to(post_path(post)) do %>
            <%= image_tag post.photos.first.image.url(:medium), class: "card-img-top" %>
          <% end %>

          <div class="card-body">
            <div class="row parts">

              <div id="like-icon-post-<%= post.id.to_s %>">
                <% if post.liked_by(current_user).present? %>
                  <%= link_to "いいねを取り消す", post_like_path(post.id, post.liked_by(current_user)), method: :DELETE, remote: true, class: "loved hide-text" %>
                <% else %>
                  <%= link_to "いいね", post_likes_path(post), method: :POST, remote: true, class: "love hide-text" %>
                <% end %>
              </div>

              <%= link_to "", "#", class: "comment" %>
            </div>

            <div id="like-text-post-<%= post.id.to_s %>">
              <%= render "like_text", { likes: post.likes } %>
            </div>

            <div>
              <span><strong><%= post.user.name %></strong></span>
              <span><%= post.caption %></span>
              <%= link_to time_ago_in_words(post.created_at).upcase + "前", post_path(post), class: "post-time no-text-decoration" %>

              <div id="comment-post-<%= post.id.to_s %>">
                <%= render 'comment_list', { post: post } %>
              </div>
              <%= link_to time_ago_in_words(post.created_at).upcase + "前", post_path(post),
                class: "light-color post-time no-text-decoration" %>
              <hr>
              <div class="row actions" id="comment-form-post-<%= post.id.to_s %>">
                <%= form_with model: [post, Comment.new], class: "w-100" do |f| %>
                  <%= f.hidden_field :user_id, value: current_user.id %>
                  <%= f.hidden_field :post_id, value: post.id %>
                  <%= f.text_field :comment, class: "form-control comment-input border-0", placeholder: "コメント ...", autocomplete: :off %>
                <% end %>
              </div>

            </div>
          </div>
        </div>
      </div>
    </div>
  <% end %>

posts_controller.rb
1class PostsController < ApplicationController
2  before_action :authenticate_user!
3  before_action :set_post, only: %i(show destroy)
4
5  def new
6    @post = Post.new
7    @post.photos.build
8  end
9
10  def create
11    @post = Post.new(post_params)
12    if @post.photos.present?
13      @post.save
14      redirect_to root_path
15      flash[:notice] = "投稿が保存されました"
16    else
17      redirect_to root_path
18      flash[:alert] = "投稿に失敗しました"
19    end
20
21    def index
22      # orderはデータベースから取り出す順序を指定
23      @posts = Post.limit(10).includes(:photos, :user).order('created_at DESC')
24    end
25
26    def show
27    end
28
29    def destroy
30      if @post.user == current_user
31        flash[:notice] = "投稿が削除されました。" if @post.destroy
32      else
33        flash[:alert] = "投稿の削除に失敗しました。"
34      end
35      redirect_to root_path
36    end
37
38  end
39
40  private
41
42    def post_params
43      # includes関連するテーブルをまとめて取得する
44      params.require(:post).permit(:caption, photos_attributes: [:image]).merge(user_id: current_user.id)
45    end
46
47    def set_post
48      @post = Post.find_by(id: params[:id])
49    end
50end

routes.rb
1Rails.application.routes.draw do
2  devise_for :users,
3    controllers: { registrations: 'registrations' }
4
5  root 'posts#index'
6
7  get '/users/:id', to: 'users#show', as: 'user'
8
9  resources :posts, only: %i(new create index show destroy) do
10    resources :photos, only: %i(create)
11    resources :likes, only: %i(create destroy)
12    resources :comments, only: %i(create destroy)
13  end
14end

試したこと

・index.html.erbに<%# if @posts.present? %>を代入するとエラーは消えますが、投稿の一覧が反映されません。
なお、newページから新規投稿後indexページに移動した場合は投稿一覧が問題なく表示されます。

補足情報（FW/ツールのバージョンなど）

・以下Post.allです。
[1] pry(main)> Post.all
Post Load (4.2ms) SELECT "posts".* FROM "posts"
=> [#<Post:0x00007fbf82f14700
id: 1,
caption: "agaghagagagag",
user_id: 1,
created_at: Mon, 22 Jul 2019 13:50:47 UTC +00:00,
updated_at: Mon, 22 Jul 2019 13:50:47 UTC +00:00>,
<Post:0x00007fbf82f1b320
id: 2,
caption: "agaghagagagag",
user_id: 2,
created_at: Tue, 23 Jul 2019 13:18:52 UTC +00:00,
updated_at: Tue, 23 Jul 2019 13:18:52 UTC +00:00>,
<Post:0x00007fbf82f1b140
id: 4,
caption: "こんにちは",
user_id: 2,
created_at: Wed, 24 Jul 2019 13:37:26 UTC +00:00,
updated_at: Wed, 24 Jul 2019 13:37:26 UTC +00:00>,
: