Update readme

README.md

@@ -86,7 +86,7 @@ ax.spines['top'].set_visible(False)
 
 plt.show()
 ```
-<img src="doc/gridded-timeseries-demo.png" width=500px>
+![](doc/gridded-timeseries-demo.png)
 
 ### Example: generate maps at specific dates ###
 
@@ -135,7 +135,7 @@ cbax.set_ylabel('Monthly rainfall (mm)', labelpad=10)
 
 plt.show()
 ```
-<img src="doc/gridded-map-demo.png" width=600px>
+![](doc/gridded-map-demo.png)
 
 
 ## Available climate variables ##