FRQ for Snapshots

Hi there,
Since I have several sites with many MP3's and/or (optmized) jpg's, and these sites have grown in the years to total sizes of > 1 GB, I noticed it's not so easy to make a daily backup via Snapshot and send it to Dropbox.

I think it would be very nice if Snapshot had the option to scan which files are already uploaded, so they don't get uploaded again. Compare with the time-machine in my macbook, it maken incremental backups (is that the right word?).
So: index all files, only upload what's necessary.

How would that be?
A few +1's ??

Best regards,