diff --git a/book/img/GHCNd.png b/book/img/GHCNd.png deleted file mode 100644 index c178070..0000000 Binary files a/book/img/GHCNd.png and /dev/null differ diff --git a/book/img/ghcnd-2.png b/book/img/ghcnd-2.png new file mode 100644 index 0000000..b26f929 Binary files /dev/null and b/book/img/ghcnd-2.png differ