removes alt attribute value

themes/edx.org/lms/templates/header.html

@@ -82,7 +82,7 @@ site_status_msg = get_site_status_msg(course_id)
           username = user.username
           profile_image_url = get_profile_image_urls_for_user(user)['medium']
           %>
-          <img class="user-image-frame" src="${profile_image_url}" alt="${_('Profile image for {username}').format(username=username)}">
+          <img class="user-image-frame" src="${profile_image_url}" alt="">
           <div class="label-username">${username}</div>
         </a>
       </li>