Index: trunk/wp-includes/formatting.php
===================================================================
--- trunk/wp-includes/formatting.php	(revision 11737)
+++ trunk/wp-includes/formatting.php	(working copy)
@@ -1317,8 +1317,10 @@
 	$smiley = trim(reset($smiley));
 	$img = $wpsmiliestrans[$smiley];
 	$smiley_masked = esc_attr($smiley);
+	
+	$srcurl = apply_filters('smilies_src', "$siteurl/wp-includes/images/smilies/$img", $img, $siteurl);
 
-	return " <img src='$siteurl/wp-includes/images/smilies/$img' alt='$smiley_masked' class='wp-smiley' /> ";
+	return " <img src='$srcurl' alt='$smiley_masked' class='wp-smiley' /> ";
 }