add compability note to image styles

docs/base-css.html

@@ -1531,7 +1531,7 @@ For example, <code>section</code> should be wrapped as inline.
             <h1>Images</h1>
           </div>
 
-          <p>Simple classes to easily style images in any project.</p>
+          <p>Simple classes to easily style images in any project. Heads up: <code>.img-rounded</code> and <code>.img-circle</code> don't work in IE7-8.</p>
           <div class="bs-docs-example bs-docs-example-images">
             <img src="http://placehold.it/140x140" class="img-rounded">
             <img src="http://placehold.it/140x140" class="img-circle">

docs/templates/pages/base-css.mustache

@@ -1468,7 +1468,7 @@
             <h1>{{_i}}Images{{/i}}</h1>
           </div>
 
-          <p>Simple classes to easily style images in any project.</p>
+          <p>{{_i}}Simple classes to easily style images in any project. Heads up: <code>.img-rounded</code> and <code>.img-circle</code> don't work in IE7-8.{{/i}}</p>
           <div class="bs-docs-example bs-docs-example-images">
             <img src="http://placehold.it/140x140" class="img-rounded">
             <img src="http://placehold.it/140x140" class="img-circle">