use sprite for icons

app/assets/stylesheets/framework/dropdowns.scss

@@ -481,7 +481,8 @@
 
 .dropdown-menu-selectable {
   li {
-    a, button {
+    a,
+    button {
       padding: 8px 40px;
       position: relative;
 

app/assets/stylesheets/snippets.scss

@@ -13,6 +13,21 @@
   margin: 20px;
   font-weight: 200;
 
+  .gl-snippet-icon {
+    display: inline-block;
+    background: url(asset_path('ext_snippet_icons/ext_snippet_icons.png')) no-repeat;
+    overflow: hidden;
+    text-indent: -9999px;
+    text-align: left;
+    width: 16px;
+    height: 16px;
+    background-size: cover;
+
+    &.gl-snippet-icon-doc_code { background-position: -0 -0;  }
+    &.gl-snippet-icon-doc_text {  background-position: -0 -16px; }
+    &.gl-snippet-icon-download {  background-position: -0 -32px; }
+  }
+
   .blob-viewer {
     background-color: $white-light;
     text-align: left;
@@ -108,7 +123,8 @@
       }
     }
 
-    img {
+    img,
+    .gl-snippet-icon {
       display: inline-block;
       vertical-align: middle;
     }

app/helpers/icons_helper.rb

@@ -44,7 +44,7 @@ module IconsHelper
   end
 
   def external_snippet_icon(name)
-    content_tag(:img, "", src: "#{image_url('/assets/ext_snippet_icons')}/#{name}.png", width: '16px', height: '16px')
+    content_tag(:span, "", class: "gl-snippet-icon gl-snippet-icon-#{name}")
   end
 
   def audit_icon(names, options = {})