title: How use dark mode and different resolution assets images in flutter?
body: <p>I use in my flutter project images with different resolutions as its described <a href="https://flutter.dev/docs/development/ui/assets-and-images#resolution-aware" rel="nofollow noreferrer">here</a>. Now I want to add custom images for dark mode theme. 
  My assets declaration in pubspec.yaml look like this:</p>
  
  <pre><code>flutter:
    uses-material-design: true
    assets:
      - assets/images/img_menu.png
      - ...
  </code></pre>
  
  <p>My assets structure:</p>
  
  <pre><code>  .../pubspec.yaml
    .../assets/images/img_menu.png
    .../assets/images/0.75x/img_menu.png
    .../assets/images/1.5x/img_menu.png
    .../assets/images/2.0x/img_menu.png
    .../assets/images/3.0x/img_menu.png
    .../assets/images/4.0x/img_menu.png
  </code></pre>
  
  <p>I load images in project this way:</p>
  
  <pre><code>Image.asset('assets/images/img_menu.png')
  </code></pre>
  
  <p>I know that for simple one color images I can change its color like that:</p>
  
  <pre><code>Image.asset('assets/images/img_menu.png', 
                        color: Theme.of(context).brightness == Brightness.light
                        ? Colors.black
                        : Colors.white,)
  </code></pre>
  
  <p>but most of my images are more complex, so I have to load custom assets for them.</p>
  
  <p>As it is described <a href="https://flutter.dev/docs/development/ui/assets-and-images#asset-variants" rel="nofollow noreferrer">here</a> I can leave pubspec without any changes after adding dark mode assets. 
  I've tried different assets structures for dark mode, but none of them works.</p>
  
  <p>1:</p>
  
  <pre><code>  .../pubspec.yaml
    .../assets/images/img_menu.png
    .../assets/images/dark/img_menu.png
    .../assets/images/0.75x/img_menu.png
    .../assets/images/0.75x/dark/img_menu.png
    .../assets/images/1.5x/img_menu.png
    .../assets/images/1.5x/dark/img_menu.png
    .../assets/images/2.0x/img_menu.png
    .../assets/images/2.0x/dark/img_menu.png
    .../assets/images/3.0x/img_menu.png
    .../assets/images/3.0x/dark/img_menu.png
    .../assets/images/4.0x/img_menu.png
    .../assets/images/4.0x/dark/img_menu.png
  </code></pre>
  
  <p>2:</p>
  
  <pre><code>  .../pubspec.yaml
    .../assets/images/img_menu.png
    .../assets/images/0.75x/img_menu.png
    .../assets/images/1.5x/img_menu.png
    .../assets/images/2.0x/img_menu.png
    .../assets/images/3.0x/img_menu.png
    .../assets/images/4.0x/img_menu.png
    .../assets/images/dark/img_menu.png
    .../assets/images/dark/0.75x/img_menu.png
    .../assets/images/dark/1.5x/img_menu.png
    .../assets/images/dark/2.0x/img_menu.png
    .../assets/images/dark/3.0x/img_menu.png
    .../assets/images/dark/4.0x/img_menu.png
  </code></pre>
  
  <p>3:</p>
  
  <pre><code>  .../pubspec.yaml
    .../assets/images/img_menu.png
    .../assets/images/0.75x/img_menu.png
    .../assets/images/1.5x/img_menu.png
    .../assets/images/2.0x/img_menu.png
    .../assets/images/3.0x/img_menu.png
    .../assets/images/4.0x/img_menu.png
    .../assets/dark/images/img_menu.png
    .../assets/dark/images/0.75x/img_menu.png
    .../assets/dark/images/1.5x/img_menu.png
    .../assets/dark/images/2.0x/img_menu.png
    .../assets/dark/images/3.0x/img_menu.png
    .../assets/dark/images/4.0x/img_menu.png
  </code></pre>
  
  <p>Solution for single image is to load it like that:</p>
  
  <pre><code>Image.asset(Theme.of(context).brightness == Brightness.light 
                        ? 'assets/images/img_menu.png'
                        : 'assets/images/dark/img_menu.png',)
  </code></pre>
  
  <p>but this is not a convenient solution for the entire project.</p>
  
  <p>What's stranger, in the 2 variant app loads dark images for both: light and dark theme (tested on iPhone and Android).</p>
  
  <p>So the question is: What should the file structure for dark mode and resolution-aware image assets look like?</p>