using @extend for responsive blocks, added shadow-box mixin to utlities for configurable border shadow box styling, moved .left, .right, .center classes to .basic-alignment class for @extending as needed in layouts. Fixes #109

.themes/classic/sass/base/_layout.scss

@@ -75,6 +75,15 @@ aside[role=sidebar] {
   @extend .group;
 }
 
+.flex-content { max-width: 100%; height: auto; }
+
+.basic-alignment {
+  &.left { float: left; margin-right: 1.5em; }
+  &.right { float: right; margin-left: 1.5em; }
+  &.center { display:block; margin: 0 auto 1.5em; }
+  &.left, &.right { margin-bottom: .8em; }
+}
+
 .toggle-sidebar { &, .no-sidebar & { display: none; }}
 
 body.sidebar-footer {

.themes/classic/sass/base/_utilities.scss

@@ -5,6 +5,13 @@
   height: image-height($img);
 }
 
+@mixin shadow-box($border: #fff .5em solid, $shadow: rgba(#000, .15) 0 1px 4px, $border-radius: .3em) {
+  @include border-radius($border-radius);
+  @include box-shadow($shadow);
+  @include box-sizing(border-box);
+  border: $border;
+}
+
 @mixin selection($bg, $color: inherit, $text-shadow: none){
   * {
     &::-moz-selection { background: $bg; color: $color; text-shadow: $text-shadow; }

.themes/classic/sass/partials/_blog.scss

@@ -44,19 +44,9 @@ article {
     line-height: 1.3em;
   }
   img, video, .flash-video {
-    max-width: 100%;
+    @extend .flex-content;
-    height: auto;
+    @extend .basic-alignment;
-    border: .5em solid #fff;
+    @include shadow-box;
-    @include border-radius(.3em);
-    @include box-shadow(rgba(#000, .15) 0 1px 4px);
-    @include box-sizing(border-box);
-    display: block;
-  }
-  img {
-    &.left { float: left; margin-right: 1.5em; }
-    &.right { float: right; margin-left: 1.5em; }
-    &.center { margin: 0 auto 1.5em; }
-    &.left, &.right { margin-bottom: .8em; }
   }
   video, .flash-video { margin: 0 auto 1.5em; }
   video { display: block; width: 100%; }

.themes/classic/sass/partials/sidebar/_base.scss

@@ -20,6 +20,11 @@ aside[role=sidebar] {
       }
     }
   }
+  img {
+    @extend .flex-content;
+    @extend .basic-alignment;
+    @include shadow-box($border: #fff .3em solid);
+  }
   ul {
     margin-bottom: 0.5em;
     margin-left: 0;