Index: wp-content/themes/twentyten/style.css
===================================================================
--- wp-content/themes/twentyten/style.css	(revision 17241)
+++ wp-content/themes/twentyten/style.css	(working copy)
@@ -359,6 +359,9 @@
 }
 
 /* This is the custom header image */
+#branding {
+	overflow: hidden;
+}
 #branding img {
 	border-top: 4px solid #000;
 	border-bottom: 1px solid #000;