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app/views/welcome/_course_list.html.erb

@@ -1,7 +1,7 @@
 <% course_list.map do |course| %>
     <li class='<%= cycle("odd", "even") %>' title="<%= course.description.to_s.gsub(/<\/?.*?>/,'') %>"  style="min-height: 69px;">
       <div class='avatar'>
-        <%= image_tag(get_course_avatar(course), :class => "avatar-4") %>
+        <%= image_tag(url_to_avatar(course), :class => "avatar-4") %>
       </div>
       <!-- 上左下右 -->
       <div class='desc_item'>