diff --git a/.github/explain.png b/.github/explain.png
new file mode 100644
index 0000000..9cea080
Binary files /dev/null and b/.github/explain.png differ
diff --git a/readme.md b/readme.md
index 2cd7ddb..5c1995c 100644
--- a/readme.md
+++ b/readme.md
@@ -66,6 +66,8 @@ const snap = getSnapPositions( scrollingElement );
 */
 ```
 
+![Diagram showing difference between function calls](.github/explain.png)
+
 ## TODO
 
 - More documentation