diff --git a/phpBB/includes/captcha/captcha_gd_wave.php b/phpBB/includes/captcha/captcha_gd_wave.php
index f706c98d43..27422513d9 100644
--- a/phpBB/includes/captcha/captcha_gd_wave.php
+++ b/phpBB/includes/captcha/captcha_gd_wave.php
@@ -62,8 +62,8 @@ class captcha
 				'y' => mt_rand(10, 17)
 			),
 			'lower_left'	=> array(
-				'x' => mt_rand($img_x - 5, $img_x - 45),
-				'y' => mt_rand($img_y - 0, $img_y - 15)
+				'x' => mt_rand($img_x - 45, $img_x - 5),
+				'y' => mt_rand($img_y - 15, $img_y - 0),
 			),
 		);