Replace images in the content to progressive figures

layouts/blog/single.html

@@ -13,7 +13,7 @@
                 </div>
             </div>
             <div class="markdown">
-                {{ .Content }}
+                {{ .Content | replaceRE "<img src=(.*)\\/(.*) alt=(.*)>" "<figure class=\"progressive\"><img class=\"progressive__img progressive--not-loaded\" data-progressive=$1/high/$2 src=$1/low/$2 alt=$3></figure>" | safeHTML }}
                 <br>
                 <p><a href="{{ .Section }}">Back to posts</a></p>
             </div>