External Website can use < img /> tag to display an image from your site somewhere else on the internet
1. Log into your cPanel account.
2. In the "Security" section, click on "HotLink Protection" Icon.
3. If it displays "Hotlink protection is currently disabled", click on the "Enable" button.
How to Configure Hotlink Protection?
Under "List the URLs to which you wish to allow access" you can allow an external website or your own