Use a directory called images instead of img.

While a lose convention, `images` is more common and more explicit.

docs/source/deployment/heroku.md

@@ -11,14 +11,14 @@ Heroku is a common Platform as a Service that allows you to deploy your Apollo S
 Log into the [Heroku dashboard](https://dashboard.heroku.com/apps). Then click “New” > “Create New App” in the top right. The name you choose will be used later in this tutorial as <HEROKU_APP_NAME>, so be sure to replace it in the later sections.
 
 <div style="text-align:center">
-![New App Screenshot](../img/deployment/heroku/new-app.png)
+![New App Screenshot](../images/deployment/heroku/new-app.png)
 <br></br>
 </div>
 
 Name your app and hit “Create app”
 
 <div style="text-align:center">
-![Create App Screenshot](../img/deployment/heroku/create-app.png)
+![Create App Screenshot](../images/deployment/heroku/create-app.png)
 <br></br>
 </div>
 
@@ -46,7 +46,7 @@ In order to enable the production mode of Apollo Server, you will need to set th
 Then under the “Settings” tab, click “Reveal Config Vars". Next set `NODE_ENV` to `production` and copy your key from the [Engine UI](http://engine.apollographql.com/) as the value for `ENGINE_API_KEY`.
 
 <div style="text-align:center">
-![Add Engine Api Key Screenshot](../img/deployment/heroku/add-env-vars.png)
+![Add Engine Api Key Screenshot](../images/deployment/heroku/add-env-vars.png)
 <br></br>
 </div>
 
@@ -59,7 +59,7 @@ Send a query to your GraphQL service at your Heroku Application at `<HEROKU_APP_
 If you have your project published to github, you are able to setup Heroku to perform automatic deployments from branch. If you have pushed your project GitHub, you may select a branch in your repository that will trigger deploys.
 
 <div style="text-align:center">
-![Add Integration Screenshot](../img/deployment/heroku/add-integration.png)
+![Add Integration Screenshot](../images/deployment/heroku/add-integration.png)
 <br></br>
 </div>