Select other sample output image

Use a smaller version image for header and larger sample output for the
footer.

README.md

@@ -47,3 +47,7 @@ Land elevation, bathymetry, and real-color maps obtained from [Visible Earth](ht
 Water mask map obtained from [Shaded Relief](https://www.shadedrelief.com/natural3/pages/extra.html).
 Uses [D3](https://d3js.org/) (d3-geo) for map projections. Super Mario is a property of Nintendo.
 [Super Mario War](http://supermariowar.supersanctuary.net/) is a fangame inspired by Super Mario games.
+
+## Samples
+
+![Larger Sample Output](./docs/img/sample-output-2.png)