title: Vue3 style directive with background-image produces 404 Error
body: <p>I am assingning a reactive <code>image link</code> fetched from a <code>database</code> through <code>axios.get</code> like so:</p>
  <pre><code>&lt;div class=&quot;main-image&quot; :style=&quot;{'background-image': 'url(' + state.articles.image[0] + ')'}&quot;&gt;
  </code></pre>
  <p>Everything works fine, the background image of the div is changed correctly. The only problem is that my console throws:</p>
  <pre><code>GET http://localhost:3000/undefined 404 (Not Found)
  </code></pre>
  <p>Apparently this indicates that the <code>url</code> is pointing to nowhere, but how is that even possible when the <code>background-image</code> is displayed correctly? Nowhere in my <code>CSS</code> have I set a <code>background-image</code> property, only <code>background: no-repeat center</code> but even if I remove those the error persists. Any ideas how to get rid of the <code>404</code>?</p>
  <p>Running <code>console.log(state.articles.image[0])</code> before sending it to the <code>template</code> produces the correct image link:</p>
  <pre><code>storage/brrAlEXfmEvoqjXiRhgalgzT9f2MfbX07Q4wDL0i.jpg
  </code></pre>
  <p>and even if I output the link in the template (in a h-tag for example) it shows the correct link, so what's wrong?</p>