Fix an undefined variable error from fbde2798688ab99cfe3fdd22746d60f0877b2c27
diff --git a/system/libraries/Image_lib.php b/system/libraries/Image_lib.php
index 6374aac..ce6c42b 100644
--- a/system/libraries/Image_lib.php
+++ b/system/libraries/Image_lib.php
@@ -1080,7 +1080,7 @@
 				$top = 0;
 				$bottom = $height - 1;
 
-				while ($top < $botttom)
+				while ($top < $bottom)
 				{
 					$ct = imagecolorat($src_img, $i, $top);
 					$cb = imagecolorat($src_img, $i, $bottom);