Users who have an account on a service such as Amazon’s S3 (http://aws.amazon.com) should have the option to use that service to store Campsite images and attachments. Under such a system, the scripts that handle image upload and storage on the local filesystem would instead write the files to the S3 ‘bucket’ via a PUT command. References to the files would also then be updated to point to the S3 web address instead of to the local filesystem. (Once stored on S3, files can be accessed by a web browser via a standard URI.)
The advantage for users is that for larger sites or sites that suddenly become more popular, S3 is able to serve the files far faster, thus removing some of the load from slower servers.