JSFiddle - React, Tailwind, and code Playground

HTML

<section id="sadrzaj">
  <aside>
    <figure>
      <img src="http://fscomps.fotosearch.com/compc/CSP/CSP991/k11942940.jpg" alt="slika mene" id="slika_mene">
      <figcaption id="fig_moje_slike">Moja slika</figcaption>
    </figure>
  </aside>
  <ul>
    <li>bla bla</li>
    <li>bla bla</li>
    <li>bla bal</li>
    <li>blabla</li>
  </ul>
</section>

CSS

figure {
  margin: 0;
}

aside {
  float: left; /* use this here */
  width: 14%; /* use the required width for image here */
}

#fig_moje_slike {
  font-size: 9px;
  text-align: left;
  width: 50%;
  margin: 0;
  display: block;
}

#sadrzaj {
  display: inline-block;
  margin: 3em auto;
  overflow: hidden; /* use this here since there is float elements as child */
}

#sadrzaj ul {
  display: block;
  float: left;
}

#sadrzaj ul li {
  margin: 15px 0;
}

#slika_mene {
 width: 100%; /* use 100% width for image since it will always fit the parent with the required width */
  height: auto;
  display: block;
}