diff --git a/actions/avatar.php b/actions/avatar.php
index 81eb23cec0..023a8414a1 100644
--- a/actions/avatar.php
+++ b/actions/avatar.php
@@ -108,7 +108,7 @@ class AvatarAction extends SettingsAction {
 
 		$user = common_current_user();
 
-		$filename = common_avatar_filename($user, image_type_to_extension($info[2]));
+		$filename = common_avatar_filename($user, image_type_to_extension($info[2]), NULL, common_timestamp());
 		$filepath = common_avatar_path($filename);
 
 		if (!move_uploaded_file($_FILES['avatarfile']['tmp_name'], $filepath)) {
@@ -166,9 +166,9 @@ class AvatarAction extends SettingsAction {
 		imagecopyresampled($image_s, $image_a, 0, 0, 0, 0,
 						   $size, $size, $square, $square);
 
-		$ext = ($avatar->mediattype == 'image/jpeg') ? ".jpg" : ".png";
+		$ext = ($avatar->mediattype == 'image/jpeg') ? ".jpeg" : ".png";
 
-		$filename = common_avatar_filename($user, $ext, $size);
+		$filename = common_avatar_filename($user, $ext, $size, common_timestamp());
 
 		if ($avatar->mediatype == 'image/jpeg') {
 			imagejpeg($image_s, common_avatar_path($filename));
diff --git a/lib/util.php b/lib/util.php
index 52f25c9d3c..9c288198cb 100644
--- a/lib/util.php
+++ b/lib/util.php
@@ -349,13 +349,13 @@ function common_render_content($text) {
 
 // where should the avatar go for this user?
 
-function common_avatar_filename($user, $extension, $size=NULL) {
+function common_avatar_filename($user, $extension, $size=NULL, $extra=NULL) {
 	global $config;
 
 	if ($size) {
-		return $user->id . '-' . $size . $extension;
+		return $user->id . '-' . $size . (($extra) ? $extra : '') . $extension;
 	} else {
-		return $user->id . '-original' . $extension;
+		return $user->id . '-original' . (($extra) ? $extra : '') . $extension;
 	}
 }
 
@@ -479,6 +479,10 @@ function common_mtrand($bytes) {
 	return $enc;
 }
 
+function common_timestamp() {
+	return date('YmdHisu');
+}
+	
 // XXX: set up gettext
 
 function _t($str) {