We'll create fresh WordPress site with Shortcode to flag installed. You have 20 minutes to test the plugin after that site we'll be deleted.
Shortcode to flag is an easy plugin, that will allow you to insert flags with shortcodes. For example, US will change to an American flag that won’t break your formatting. The height of the flags is 40pixels.
Put country code (in capital letters) to shortcode to display desired flag.
e.g. [US]
If you want to change height of the flags, do so in file flagstyle.css