diff --git a/lib/monster_id/monster.rb b/lib/monster_id/monster.rb
index 50a1840..9973837 100644
--- a/lib/monster_id/monster.rb
+++ b/lib/monster_id/monster.rb
@@ -1,4 +1,4 @@
-require 'chunky_png'
+require 'oily_png'
 require 'digest'
 require 'base64'