Amazon S3 storage
Amazon S3 storage library allows you to free up space on your server by storing uploaded user files at Amazon S3
To be able to use this library you must create a bucket and access keys (access key ID and secret access key) in your Amazon console. Make sure to grant public "read" access to your bucket and "write" access to your own account. Once created, fill in the bucket name, region, access key ID and secret access key on the Amazon S3 configuration page in the control panel.
Bucket folder setting allows you to optionally specify folder name within a bucket you would like the software to use when uploading files. If you leave it empty software will upload files directly into the bucket's root folder.
Custom domain setting allows you to use an alias for your Amazon bucket URI so instead of seeing something like this in your image links https://s3.us-west-2.amazonaws.com/my-bucket/you will see something like this https://www.mysite.com/my-images This alias can usually be created in your hosting control panel. If you're not sure how to do that you may contact your hosting provider for assistance. If you leave it empty software will use default Amazon URI which is also fine.