diff --git a/docs/articles/bing_quadkeys.jpg b/docs/articles/bing_quadkeys.jpg
new file mode 100644
index 0000000..813bd59
Binary files /dev/null and b/docs/articles/bing_quadkeys.jpg differ
diff --git a/vignettes/bing_quadkeys.jpg b/vignettes/bing_quadkeys.jpg
new file mode 100644
index 0000000..813bd59
Binary files /dev/null and b/vignettes/bing_quadkeys.jpg differ