Added instructions to export to an image.

Author: alexmillane

project/README.md

@@ -1,9 +1,12 @@
 # Local Mermaid Preview Setup
 
-## Install live-server
+## Install node deps
+
+Install live-server for viewing in browser and the mermaid tool for exporting.
 
 ```bash
 npm install -g live-server
+npm install -g @mermaid-js/mermaid-cli
 ```
 
 ---
@@ -16,3 +19,11 @@ live-server
 ```
 
 This starts a local server with auto-refresh for your Mermaid diagrams.
+
+## Export to an image
+
+This exports at four times the standard resolution.
+
+```bash
+mmdc -i diagram.mmd -o diagram.png -s 4 -w 2000
+```