Put ::after content to a div that is parent of element with specific class

Question

I have this markup:

<div class="parent">
   <img class="selected child"/>
</div>
<div class="parent">
   <img class="child"/>
</div>

What I would like to do is to make an :after to the "parent" div that has class=selected only.

That means I'd like to make :after to the first one, because it has a child with class "selected".

I can not use:

.parent:after .selected {}

If I use

.parent .selected:after {}

it is not good as the img get :after content and it doesn't work, I need to put :after to the parent of the image.