Honestly, I'd just buy more storage. Storage is cheap and has far fewer moving parts than proprietary compression tech.
100GB of Amazon S3 storage is $2.41 a month (after you burn up the generous free tier). So 100GB for 2 years costs about the same as the s/w. You'll pay more to have that on your website with no hassle but not a lot more. TSO Host for example will charge you £3.99 for a fixed storage account but only £6.99 for "unlimited" storage.