To avoid other sites to use your website's bandwidth, you can enable the hot link protection. This occurs when there multiple images on your website. Here are the steps to enable the hot link protection -
1. Login to cPanel.
2. Click on Hotlink Protection.
2. Click on Hotlink Protection.
3. Enter the domain names (with www and without www) that are allowed to use your files
4. List the file names which you would like to protect. Separate the file names by commas.
You can add the code in '.htaccess' file too for it. But using cPanel it's just one click option.