fixes #3291: remove float on responsive .thumbnails for 767px and down to ensure thumbnail images don't pop out of container in FF

docs/assets/css/bootstrap-responsive.css

@@ -805,7 +805,11 @@
     display: block;
     float: none;
     width: auto;
+    max-width: 100%;
     margin-left: 0;
+    -webkit-box-sizing: border-box;
+       -moz-box-sizing: border-box;
+            box-sizing: border-box;
   }
   .input-large,
   .input-xlarge,

less/responsive-767px-max.less

@@ -51,6 +51,9 @@
   .thumbnails {
     margin-left: 0;
   }
+  .thumbnails > li {
+    float: none;
+  }
   // Make all grid-sized elements block level again
   [class*="span"],
   .row-fluid [class*="span"] {