画像や大きさによって、画質が悪くなってしまう。

今現在、image_uploaderを使い、画像を表示しているのですが、画像や画像の大きさにより、画像の画質が悪くなっています。image_uploaderのリサイズなどで調整をしているつもりなのですが、機能していない状態にいます。もしわかる方がいらしたら、教えていただけたら、嬉しいです。

plans/index.html.erb

plans/show.html.erb

uploaders/image_uploader.rb

 class ImageUploader < CarrierWave::Uploader::Base
  # Include RMagick or MiniMagick support:
  #画像形式を変更するのに必要
  include CarrierWave::RMagick
  # include CarrierWave::MiniMagick

  # Choose what kind of storage to use for this uploader:
  storage :file
  # storage :fog

  # Override the directory where uploaded files will be stored.
  # This is a sensible default for uploaders that are meant to be mounted:
  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  # Provide a default URL as a default if there hasn't been a file uploaded:
  # def default_url(*args)
  #   # For Rails 3.1+ asset pipeline compatibility:
  #   # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))
  #
  #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
  # end
  #画像をリサイズする
  process :resize_to_limit => [400, 950]
  
  # Process files as they are uploaded:
  # process scale: [200, 300]
  #
  # def scale(width, height)
  #   # do something
  # end
  #保存形式をJGにする
  process :convert => 'jpg'
  # Create different versions of your uploaded files:
  #サムネイルを生成する設定
  version :thumb do
     process :resize_to_limit => [300, 300]
  end

  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
  #これらからしか保存できない
  def extension_whitelist
     %w(jpg jpeg gif png)
  end

  # Override the filename of the uploaded files:
  # Avoid using model.id or version_name here, see uploader/store.rb for details.
  #ファイルをコンパイルする
  def filename
     super.chomp(File.extname(super))+'jpg' if original_filename.present?
  end
end

plans/index.html.erb
1<div class="contents center">
2   <% @plans.each do |plan| %>
3    <div class="content_post" style="background-image: url(<%= plan.image %>);" >
4        <div class="more">
5          
6           <ul class="more_list">
7            <li>
8              <%= link_to '', "/plans/#{plan.id}", method: :get %>
9            </li>
10            
11           </ul>
12        </div>
13        <%= simple_format(plan.title) %>
14      <span class="name">
15        <a href="/guiders/<%= plan.guider_id %>">
16          <span>guider</span><%= plan.guider.nickname %>
17        </a>
18      </span>
19
20    </div>
21
22   <% end %>
23   <%= paginate(@plans) %>
24  
25  
26 </div>

plans/show.html.erb
1<div class="main">
2    <i class="fas fa-chevron-circle-left" aria-hidden="true" id="prev"></i>
3    <img src="<%= @plan.image %>" id="target" style="width: 950px; max-width: 100%; height: 400px; padding-bottom: 15px; padding-top: 20px; ">
4    <i class="fas fa-chevron-circle-right" aria-hidden="true" id="next"></i>
5  </div>
6  <div class="king">
7    <ul class="example">
8        <li class="current"><img src="<%= @plan.image %>" alt="写真1" style=" width: 185px; height: 123px;"></li>
9        <li><img src="<%= @plan.second_image %>" alt="写真2" style="width: 185px; height: 123px;"> 
10        </li>
11        <li><img src="<%= @plan.third_image %>" alt="写真3" style="width: 185px; height: 123px;"> 
12        </li>
13        <li><img src="<%= @plan.fourth_image %>" alt="写真4" style="width: 185px; height: 123px;"> 
14        </li>
15        <li><img src="<%= @plan.five_image %>" alt="写真5" style="width: 185px; height: 123px;"> 
16        </li>
17        
18    </ul>
19  </div>
20</div>