add command-methods overview png.

Overview-of-Command-Methods.md

@@ -2,6 +2,6 @@ There is nothing special about command-methods. They are nothing more than the m
 
 Here is a diagram to help show the "position" of the command-methods within the project.
 
-IMAGES OF PROJECT LAYOUT.
+![command-methods overview](attachments/command-methods-overview.png)
 
 As an aside, the term command-methods is a C# quirk. I am aware F# is more precise with its use of "method" and "function". But, "command-methods" were already established before I began learning F#. So, I am using "command-methods" to remain consistent with the main C.W. repositories and terminology. I am well aware "command-functions" is a more accurate description.