diff --git a/gtk/gtkstylecontext.h b/gtk/gtkstylecontext.h
index 1a29c5174c..8d8f51153f 100644
--- a/gtk/gtkstylecontext.h
+++ b/gtk/gtkstylecontext.h
@@ -400,6 +400,13 @@ struct _GtkStyleContextClass
  */
 #define GTK_STYLE_CLASS_SIDEBAR "sidebar"
 
+/**
+ * GTK_STYLE_CLASS_IMAGE:
+ *
+ * A widget class defining an image, such as the icon in an entry.
+ */
+#define GTK_STYLE_CLASS_IMAGE "image"
+
 /**
  * GTK_STYLE_CLASS_HIGHLIGHT:
  *