JAlbum uses FTP to upload, so if Amazon lets you upload via FTP then use jAlbum’s built in FTP. You can also upload your albums outside of JAlbum, the album is just a folder of files.

It would appear you can use drag and drop if using Amazon’s S3 console, https://docs.aws.amazon.com/AmazonS3/latest/user-guide/upload-objects.html
But it only supports certain versions of Chrome and Firefox browsers.

Whatever that means, they are claiming:

Getting started with AWS Transfer for SFTP (AWS SFTP) is simple. Create an SFTP server and map your domain to the server endpoint, select authentication for your SFTP clients using service-managed identities, or integrate your own identity provider, and select your Amazon S3 buckets to store the transferred data. Your existing users can continue to operate with their existing SFTP clients or applications. Data uploaded or downloaded using SFTP is available in your Amazon S3 bucket, and can be used for archiving or processing in AWS.

https://aws.amazon.com/about-aws/whats-new/2018/11/aws-transfer-for-sftp-fully-managed-sftp-for-s3/

This is really a bargain when compared to Mercedes Maybach Rental: Price starting from €1400/Per Day.

On the other hand operating systems nowadays come with built in ftp servers. Turning them on is as easy as turning on living room lights.