title: Include image in Jekyll markdown collection
body: <p>I created a custom collection in my Jekyll configuration:</p>
  
  <pre><code>collections:
    tutorials:
      output: true
      permalink: /tutorials/:path/
  </code></pre>
  
  <p>I have a markdown file with the path: <code>_tutorial/category/ios.md</code>
  I also have an image with the path: <code>_tutorial/category/xcode.png</code></p>
  
  <p>In <strong>ios.md</strong> I use:
  <code>![xcode](xcode.png)</code></p>
  
  <p>Which should make sense since they are on the same directory.</p>
  
  <p>In the <strong>_site</strong> generated folder, I see</p>
  
  <pre><code>tutorial/
    category/
      xcode.png
      ios/
        index.html
  </code></pre>
  
  <p>So obviously the generated HTML is looking at the wrong place for the image since they are no longer in the same directory.</p>
  
  <p>I thought of changing my structure to have my markdown file be <code>_tutorial/category/ios/index.md</code>, however all it did was create a folder called <code>index</code> so the problem is the same.</p>
  
  <p>What is the expected way to include images in Jekyll/Markdown?</p>
  
  <p>Am I supposed to keep them all in a folder at the root of the site? That would obviously work but it makes it hard to keep track of which images are associated with each post...</p>