factor out avatar <img> code to show 2x version everywhere

app/helpers/application_helper.rb

@@ -1,6 +1,15 @@
 module ApplicationHelper
   MAX_PAGES = 15
 
+  def avatar_img(user, size)
+    image_tag(user.avatar_url(size), {
+      :srcset => "#{user.avatar_url(size)} 1x, " <<
+        "#{user.avatar_url(size * 2)} 2x",
+      :class => "avatar",
+      :size => "#{size}x#{size}",
+      :alt => "#{user.username} avatar" })
+  end
+
   def break_long_words(str, len = 30)
     safe_join(str.split(" ").map{|w|
       if w.length > len

app/views/comments/_comment.html.erb

@@ -38,8 +38,8 @@ class="comment <%= comment.current_vote ? (comment.current_vote[:vote] == 1 ?
       <% end %>
 
       <% if (@user && @user.show_avatars?) || !@user %>
-        <a href="/u/<%= comment.user.username %>"><img
-          src="<%= comment.user.avatar_url(16) %>" class="avatar"></a>
+        <a href="/u/<%= comment.user.username %>"><%=
+          avatar_img(comment.user, 16) %></a>
       <% end %>
 
       <a href="/u/<%= comment.user.username %>"

app/views/stories/_listdetail.html.erb

@@ -62,10 +62,8 @@ class="story <%= story.vote && story.vote[:vote] == 1 ? "upvoted" : "" %>
           <% end %>
           <span class="byline">
             <% if (@user && @user.show_avatars?) || !@user %>
-              <a href="/u/<%= ms.user.username %>"><img
-                src="<%= ms.user.avatar_url(16) %>"
-                srcset="<%= ms.user.avatar_url(16) %> 1x,
-                <%= ms.user.avatar_url(32) %> 2x" class="avatar"></a>
+              <a href="/u/<%= ms.user.username %>"><%=
+                avatar_img(ms.user, 16) %></a>
             <% end %>
             <% if story.user_is_author? %>
               <%= t('.authoredby') %>
@@ -92,10 +90,8 @@ class="story <%= story.vote && story.vote[:vote] == 1 ? "upvoted" : "" %>
 
     <div class="byline">
       <% if (@user && @user.show_avatars?) || !@user %>
-        <a href="/u/<%= story.user.username %>"><img
-          src="<%= story.user.avatar_url(16) %>"
-          srcset="<%= story.user.avatar_url(16) %> 1x,
-          <%= story.user.avatar_url(32) %> 2x" class="avatar"></a>
+        <a href="/u/<%= story.user.username %>"><%=
+          avatar_img(story.user, 16) %></a>
       <% end %>
       <% if story.previewing %>
         <% if story.user_is_author? %>

app/views/users/show.html.erb

@@ -17,9 +17,7 @@
 
   <% if @showing_user.is_active? %>
     <div id="gravatar">
-      <img src="<%= @showing_user.avatar_url(100) %>"
-        srcset="<%= @showing_user.avatar_url(100) %> 1x,
-        <%= @showing_user.avatar_url(200) %> 2x">
+      <%= avatar_img(@showing_user, 100) %>
     </div>
   <% end %>