SVG images in AMP article Microdata?
<p>When attempting to validate a <code>schema.org/Article</code> against Google's <a href="https://developers.google.com/structured-data/testing-tool/" rel="nofollow">Structured Data Testing Tool</a>, I noticed that it gives an error if you specify an SVG image:</p>

<blockquote>
  <p>The value provided for <em>logo</em> must be a valid URL.</p>
  
  <p><strong>Required by:</strong></p>
  
  <p>AMP Articles (<a href="https://developers.google.com/structured-data/rich-snippets/articles" rel="nofollow">what's this?</a>)</p>
</blockquote>

<p>When the URL is changed to have a <code>.png</code> (or <code>.jpg</code>, <code>.bmp</code>, <code>.webp</code>, etc.) extension, rather than <code>.svg</code>, it passes validation.</p>

<p>Here is the example I'm working with:</p>

<pre class="lang-html prettyprint-override"><code>&lt;div itemscope itemtype="http://schema.org/Article"&gt;
    &lt;div itemprop="publisher" itemscope itemtype="https://schema.org/Organization"&gt;
        &lt;meta itemprop="name" content="Example" /&gt;
        &lt;meta itemprop="url" content="http://example.com" /&gt;
        &lt;div itemprop="logo" itemscope itemtype="https://schema.org/ImageObject"&gt;
            &lt;meta itemprop="url" content="http://example.com/logo.svg" /&gt;
            &lt;meta itemprop="width" content="600" /&gt;
            &lt;meta itemprop="height" content="60" /&gt;
        &lt;/div&gt;
    &lt;/div&gt;
    &lt;meta itemprop="dateModified" content="2016-01-05T12:43" /&gt;
    &lt;meta itemprop="datePublished" content="2016-01-05T12:43" /&gt;
    &lt;meta itemprop="headline" content="Example" /&gt;
    &lt;meta itemprop="name" content="Example" /&gt;
    &lt;meta itemprop="author" content="Example" /&gt;
    &lt;link itemprop="mainEntityOfPage" href="http://example.com/article" /&gt;
    &lt;div itemprop="image" itemscope itemtype="https://schema.org/ImageObject"&gt;
        &lt;meta itemprop="url" content="http://example.com/article.jpg" /&gt;
        &lt;meta itemprop="width" content="1200" /&gt;
        &lt;meta itemprop="height" content="800" /&gt;
    &lt;/div&gt;
&lt;/div&gt;
</code></pre>

<p>Changing the other image's URL's extension will also produce the error.</p>

<p>I was unable to find any information on why it rejects SVGs in the <a href="https://developers.google.com/structured-data/rich-snippets/articles#article_markup_properties" rel="nofollow">Rich Snippets documentation</a> or the <a href="https://github.com/ampproject/amphtml/tree/master/spec" rel="nofollow">AMP HTML spec</a>. Does anyone have an explanation for this behavior?</p>