Update image path to use a helper method

templates/base_public.html

@@ -18,7 +18,7 @@
 
   <div class="usa-banner-header">
     <div class="usa-grid usa-banner-inner">
-      <img src="static/img/us_flag.png" alt="U.S. flag">
+      <img src="{{url_for('static', filename='img/us_flag.png')}}" alt="U.S. flag">
       <p>An official website of the United States government</p>
       <button class="usa-accordion-button usa-banner-button" aria-expanded="false" aria-controls="gov-banner">
         <span class="usa-banner-button-text">Here’s how you know</span>
@@ -26,6 +26,7 @@
     </div>
   </div>
 
+
   <header class="topbar topbar--public">
     <nav class="topbar__navigation">
       <a href="{{ url_for('atst.home') }}" class="topbar__link topbar__link--home">