typo fix
diff --git a/user_guide/libraries/image_lib.html b/user_guide/libraries/image_lib.html
index d3fbe27..7c950f3 100644
--- a/user_guide/libraries/image_lib.html
+++ b/user_guide/libraries/image_lib.html
@@ -451,7 +451,7 @@
$config['wm_type'] = 'text';<br />
$config['wm_font_path'] = './system/fonts/texb.ttf';<br />
$config['wm_font_size'] = '16';<br />
-$config['wm_text_color'] = 'ffffff';<br />
+$config['wm_font_color'] = 'ffffff';<br />
$config['wm_vrt_alignment'] = 'bottom';<br />
$config['wm_hor_alignment'] = 'center';<br />
$config['wm_padding'] = '20';<br />