Move .img- classes to new _images.scss; move hr to _type.scss

scss/_images.scss

@@ -0,0 +1,28 @@
+// Responsive images (ensure images don't scale beyond their parents)
+.img-responsive {
+  @include img-responsive();
+}
+
+// Rounded corners
+.img-rounded {
+  @include border-radius($border-radius-lg);
+}
+
+// Image thumbnails
+.img-thumbnail {
+  padding: $thumbnail-padding;
+  line-height: $line-height-base;
+  background-color: $thumbnail-bg;
+  border: 1px solid $thumbnail-border;
+  border-radius: $thumbnail-border-radius;
+  transition: all .2s ease-in-out;
+  @include box-shadow(0 1px 2px rgba(0,0,0,.075));
+
+  // Keep them at most 100% wide
+  @include img-responsive(inline-block);
+}
+
+// Perfect circle
+.img-circle {
+  border-radius: 50%; // set radius in percents
+}