You can set up an S3 source using the LibPixel dashboard, enable upload support, and choose an access control setting for the uploaded images (public-read or private).
To learn more about the LibPixel Uploader, and how to use it, head over to the GitHub repo.
If you want to prevent your S3 images from being accessed directly by anyone on the internet, and only through LibPixel (i.e. S3 objects with a private ACL), you can now do so by configuring your image source as an S3 source in the LibPixel dashboard, and specifying IAM credentials that allow access to the S3 bucket.
You can learn more about S3 sources in the documentation.
LibPixel runs on AWS, so by using S3 in the same AWS region as LibPixel, you'll have the lowest possible latency to your image source, and you won’t even have to pay for the bandwidth between your bucket and our servers.