I found a temporary solution.
If you have an FTP. Go to the plugin files. find folder modules > info-list > includes > frontend.css.php and then go to line 379 – 381. The image sizes are not integers. I used this code:
if ( (null !== intval($img_size[0]) ) && ( null !== intval($img_size[1]) ) && (0 !== intval($img_size[0]) )) :
$actual_height = ( intval($settings->icon_image_size) * intval($img_size[1] )) / intval($img_size[0]);