Craft asset urls not working
As per the Craft Docs at https://craftcms.com/docs/multi-environment-configs#environment-specific-variables, add a basePath (or other name) variable to you config. For MAMP, it should look something like:

'basePath' =&gt; '/Applications/MAMP/htdocs/example.dev/public/'

Then in your asset source settings, change File System Path to:

{basePath}assets/images/hero-images/