So I made a custom images to be language switcher in a way that I put them in flags folder and renamed them in en_us.png and so.
I've used the following code to display the image link in header
<div id="lang"><?php pll_the_languages(array('hide_current'=>1, 'show_flags'=>1, 'show_names'=>0));?></div>
The problem is that I don't know how to remove bullet from link. :-/