fix broken link to architecture.md, and convert architecture pdfs to pngs
diff --git a/README.md b/README.md
index 5567e0c..5625fed 100644
--- a/README.md
+++ b/README.md
@@ -90,7 +90,7 @@
 
 ## Notes on the Architecture
 
-If you are curious as to the inner workings of the debugger, you can read more [here](docs/architecture.md). In short, `wskdb` operates by graph rewriting. In a way reminiscent of conventional debuggers, `wskdb` will install a *trampoline* that allows insertion of a breakpoint that re-routes invocations to your local machine.
+If you are curious as to the inner workings of the debugger, you can read more [here](docs/architecture/architecture.md). In short, `wskdb` operates by graph rewriting. In a way reminiscent of conventional debuggers, `wskdb` will install a *trampoline* that allows insertion of a breakpoint that re-routes invocations to your local machine.
 
 ### License
 
diff --git a/docs/architecture/architecture.md b/docs/architecture/architecture.md
index 9d305fc..bce263f 100644
--- a/docs/architecture/architecture.md
+++ b/docs/architecture/architecture.md
@@ -10,8 +10,8 @@
 
 We will continue to flesh out this section. 
 
-![Successful Invocations](offload_successful_invocation.pdf "Routing of a successful invocation")
+![Successful Invocations](offload_successful_invocation.png "Routing of a successful invocation")
 
-![Aborted Invocations](offload_aborted_invocation.pdf "Routing of an aborted invocation")
+![Aborted Invocations](offload_aborted_invocation.png "Routing of an aborted invocation")
 
-![Handling Sequences](offload_sequence.pdf "Routing of an action sequence")
+![Handling Sequences](offload_sequence.png "Routing of an action sequence")