added alt tags to course cover images and find course page logo

lms/templates/course.html

@@ -19,7 +19,7 @@
       </header>
       <section class="info">
         <div class="cover-image">
-          <img src="${course_image_url(course)}">
+          <img src="${course_image_url(course)}" alt="${course.number} ${get_course_about_section(course, 'title')} Cover Image" />
         </div>
         <div class="desc">
           <p>${get_course_about_section(course, 'short_description')}</p>

lms/templates/courseware/courses.html

@@ -10,9 +10,9 @@
       <hgroup>
         <div class="logo">
           % if self.stanford_theme_enabled():
-            <img src="${static.url('themes/stanford/images/seal.png')}" />
+            <img src="${static.url('themes/stanford/images/seal.png')}" alt="Stanford Seal Logo" />
           % else:
-            <img src="${static.url('images/edx_bw.png')}" />
+            <img src="${static.url('images/edx_bw.png')}" alt="Black and White edX Logo" />
           % endif
         </div>
         % if self.stanford_theme_enabled():

lms/templates/dashboard.html

@@ -211,11 +211,11 @@
 
           % if course.id in show_courseware_links_for:
             <a href="${course_target}" class="cover">
-              <img src="${course_image_url(course)}" />
+              <img src="${course_image_url(course)}" alt="${course.number} ${course.display_name_with_default} Cover Image" />
             </a>
           % else:
             <div class="cover">
-              <img src="${course_image_url(course)}" />
+              <img src="${course_image_url(course)}" alt="${course.number} ${course.display_name_with_default} Cover Image" />
             </div>
           % endif