add image back in comment

Author: vanfossen

.devcontainer/devcontainer.json

@@ -2,13 +2,16 @@
 // README at: https://github.com/devcontainers/templates/tree/main/src/docker-existing-dockerfile
 {
 	"name": "Existing Dockerfile",
+
 	"build": {
 		// Sets the run context to one level up instead of the .devcontainer folder.
 		"context": "..",
 		// Update the 'dockerFile' property if you aren't using the standard 'Dockerfile' filename.
 		"dockerfile": "../Dockerfile"
 	},
 
+	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+	// "image": "mcr.microsoft.com/devcontainers/python:1-3.10",
 
 	// Features to add to the dev container. More info: https://containers.dev/features.
 	"features": {