elegantmodules

SyncS3 gives Gravity Forms users the ability to push any files to any Amazon S3 bucket. When files are submitted through a form, you can send those files to any Amazon account, and any S3 bucket. Simply add your Amazon AWS credentials, chose which fields should push to S3, and save.
You can even send different file-upload fields to different accounts or buckets. SyncS3 gives you flexible control over which accounts/buckets for sending your files by controlling the settings on global, form, and field levels.
If it doesn’t make sense for you to also store the files locally, you can set the files to be removed from your server after they’re uploaded to S3. This helps reduce the overall disk space of your website.
SyncS3 also includes a WP CLI command for processing all entries, so you can effortlessly send all of your files from all of your form entries to your S3 buckets.
Want to know more about SyncS3? Read about <a href="https://elegantmodules.com/modules/syncs3-gravity-forms/?utm_source=syncs3_lite&utm_medium=link&utm_campaign=readme&utm_content=syncs3_upgrade" rel="nofollow ugc">SyncS3’s features</a>.

SyncS3 Lite

Push and sync Gravity Forms file uploads to your Amazon S3 buckets.

joetan

This WordPress plugin allows you to use Amazon’s Simple Storage Service to host your media for your WordPress powered blog.
Amazon S3 is a cheap and cost effective way to scale your site to easily handle large spikes in traffic (such as from Digg) without having to go through the expense of setting up the infrastructure for a content delivery network.
Once setup, this plugin transparently integrates with your WordPress blog. File uploads are automatically saved into your Amazon S3 bucket without any extra steps. Once saved, these files will be delivered by Amazon S3, instead of your web host. Any image thumbnails that get created are saved to Amazon S3 too. You’ll also find an “Amazon S3” tab next to your regular “Upload” tab, which allows you to easily browse and manage files that were not upload via WordPress.
<h3>Documentation</h3>
If you need more help installing and configuring the plugin, <a href="http://code.google.com/p/wordpress-s3/wiki/Documentation" rel="nofollow ugc">see here for more information</a>.

Amazon S3 for WordPress

Allows you to mirror your WordPress media uploads over to Amazon S3 for storage and delivery.

SyncS3 Lite vs Amazon S3 for WordPress