Index: wp-content/themes/twentythirteen/style.css
===================================================================
--- wp-content/themes/twentythirteen/style.css	(revision 23453)
+++ wp-content/themes/twentythirteen/style.css	(working copy)
@@ -1012,6 +1012,7 @@
 	word-wrap: break-word;
 }
 
+.page.sidebar .entry-thumbnail,
 .entry-header,
 .entry-content,
 .entry-summary,
@@ -1021,6 +1022,7 @@
 	width: 100%;
 }
 
+.page.sidebar .entry-thumbnail,
 .sidebar .entry-header,
 .sidebar .entry-content,
 .sidebar .entry-summary,