update README w/ full scale model photo + caption

Author: capsulecorplab

README.md

@@ -1,9 +1,10 @@
 # RepRap Chinampa
 
-![](./reprap-chinampa-half-scale.jpg)
-
 Passive self-watering 3D-printable floating vegetable pot, inspired by the chinampa (floating garden bed).
 
+![](./reprap-chinampa-satsumaimo.jpeg)
+*Full scale model with satsuma imo (Japanese sweet potato)*
+
 ## 3D Printing Notes
 
 ### 3D Printer (Hardware) Configuration/Modifications