This is a recurring issue, especially for Drupal beginners, but it seems that the proper best practice is not well-explained.
To address this correctly, follow these steps:
- Execute the command:
$ chmod 775 -R /~/public_html/sites/default/files
This command sets the permissions of your "files" directory and all its contents to 775. This means that both the owner and group have full permissions, while the public has read and execute permissions, but not write permissions.