title: Why does box-shadow look different than filter: drop-shadow
body: <p>I've always been using CSS box-shadows since, but now I have an image with rounded corners and wanted to give it a rounded shadow. So I tried using filter: drop-shadow, but unfortunately it looks different from box-shadow. In my opinion, they should look the same, am I doing something wrong?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="false" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>td {
    padding: .5em 3em;
  }
  .box-shadow img {
     box-shadow: 0 0 10px rgba(0, 0, 0, 0.7);
  }
  .drop-shadow img {
     filter: drop-shadow(0 0 10px rgba(0, 0, 0, 0.7));
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;table&gt;
    &lt;tr&gt;
      &lt;th&gt;box shadow&lt;/th&gt;&lt;th&gt;drop shadow&lt;/th&gt;
    &lt;/tr&gt;
    &lt;tr&gt;
      &lt;td class="box-shadow"&gt;
        &lt;img src="https://placeholdit.imgix.net/~text?txtsize=33&amp;txt=350%C3%97150&amp;w=150&amp;h=150" alt="" /&gt;
      &lt;/td&gt;
      &lt;td class="drop-shadow"&gt;
        &lt;img src="https://placeholdit.imgix.net/~text?txtsize=33&amp;txt=350%C3%97150&amp;w=150&amp;h=150" alt="" /&gt;
      &lt;/td&gt;
    &lt;/tr&gt;
  &lt;/table&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>Is the appearance of these shadows defined in any spec, or do browsers just what they think they should do? Why do those look different?</p>
  
  <p>Chrome/OS X:
  <a href="https://i.stack.imgur.com/0Acbt.png" rel="noreferrer"><img src="https://i.stack.imgur.com/0Acbt.png" alt="enter image description here"></a></p>
  
  <p>Firefox/OS X:
  <a href="https://i.stack.imgur.com/B4CVz.png" rel="noreferrer"><img src="https://i.stack.imgur.com/B4CVz.png" alt="enter image description here"></a></p>