Index: src/js/media/views/frame/edit-attachments.js
===================================================================
--- src/js/media/views/frame/edit-attachments.js	(revision 57636)
+++ src/js/media/views/frame/edit-attachments.js	(working copy)
@@ -244,7 +244,7 @@
 	},
 
 	hasPrevious: function() {
-		return ( this.getCurrentIndex() - 1 ) > -1;
+		return ( this.getCurrentIndex() - 1 ) > -1 || this.getCurrentIndex() === -1;
 	},
 	/**
 	 * Respond to the keyboard events: right arrow, left arrow, except when