diff --git a/img/zeroptr.png b/img/zeroptr.png
new file mode 100644
index 0000000..20f5c4e
Binary files /dev/null and b/img/zeroptr.png differ
diff --git a/img/zptr.gif b/img/zptr.gif
deleted file mode 100644
index 9c4bd38..0000000
Binary files a/img/zptr.gif and /dev/null differ
diff --git a/index.html b/index.html
index 5828037..5515db0 100644
--- a/index.html
+++ b/index.html
@@ -506,7 +506,7 @@
-
+