diff --git a/system/helpers/captcha_helper.php b/system/helpers/captcha_helper.php
index a67b72b..94779e4 100644
--- a/system/helpers/captcha_helper.php
+++ b/system/helpers/captcha_helper.php
@@ -333,7 +333,7 @@
 			return FALSE;
 		}
 
-		$img = '<img '.($img_id === '' ? '' : 'id="'.$img_id.'"').' src="'.$img_url.$img_filename.'" style="width: '.$img_width.'; height: '.$img_height .'; border: 0;" alt=" " />';
+		$img = '<img '.($img_id === '' ? '' : 'id="'.$img_id.'"').' src="'.$img_url.$img_filename.'" style="width: '.$img_width.'px; height: '.$img_height .'px; border: 0;" alt=" " />';
 		ImageDestroy($im);
 
 		return array('word' => $word, 'time' => $now, 'image' => $img, 'filename' => $img_filename);