add scaling img (#348)

README.md

@@ -19,16 +19,15 @@
   </a>
 </p>
 
-<p align="justify">
-  Welcome to the home of MFC!
-  MFC simulates compressible multi-component and multi-phase flows, amongst other things. 
-  It scales <b>ideally to exascale</b>; tens of thousands of GPUs on NVIDIA- and AMD-GPU Machines, like Oak Ridge Summit and Frontier.
-  MFC is written in Fortran and makes use of metaprogramming to keep the code short (about 20K lines).
+Welcome to the home of MFC!
+MFC simulates compressible multi-component and multi-phase flows, amongst other things. 
+It scales <b>ideally to exascale</b>; [tens of thousands of GPUs on NVIDIA- and AMD-GPU Machines](#is-this-really-exascale), like Oak Ridge Summit and Frontier.
+MFC is written in Fortran and makes use of metaprogramming to keep the code short (about 20K lines).
 
-  Get in touch with the maintainers, like <a href="mailto:shb@gatech.edu">Spencer</a>, if you have questions!
-  We have an active Slack channel and development team.
-  MFC has high-level documentation, visualizations, and more on [its website](https://mflowcode.github.io/).
-</p>
+Get in touch with the maintainers, like <a href="mailto:shb@gatech.edu">Spencer</a>, if you have questions!
+We have an [active Slack channel](https://join.slack.com/t/mflowcode/shared_invite/zt-y75wibvk-g~zztjknjYkK1hFgCuJxVw) and development team.
+MFC has high-level documentation, visualizations, and more on [its website](https://mflowcode.github.io/).
+
 
 ## An example
 
@@ -72,6 +71,16 @@ The shock-droplet interaction case above was run via
 where `8` is the number of cores the example will run on.
 You can visualize the output data, located in `examples/3d_shockdroplet/silo_hdf5`, via Paraview, Visit, or your other favorite software.
 
+## Is this really exascale
+
+[OLCF Frontier](https://www.olcf.ornl.gov/frontier/) is the first exascale supercomputer.
+The weak scaling of MFC on this machine is below, showing near-ideal utilization. 
+
+<p align="center">
+    <img src="docs/res/scaling.png" alt="Scaling" width="400"/>
+</p>
+
+
 ## What else can this thing do
 
 MFC has many features.