How to Choose First letter, after IMG

Have many code fragments on page (30+) like this. Img + text.

 <li class="list-group-item">
<img src="img/ins/ptych-mol.jpg" height="40px" alt="" srcset="">
 some text </li>

How to choose in css only first letter uppercase of text? Need to do “Some text” in every case.
:first-letter is not working, because img tag…

  <span>Apply :first-letter to me</span>