That would be impossible for your data directory to grow from deleting images sorry but that would not be.
You can do your own test upload and image and then delete it. Was it deleted from the server?
Your data directory stats seem very reasonable and inline. Your total image size being about 58% of the total data directory. That would means your actual directories thumbnails and mediums would comprise the other 42%. That is not out of whack in any regard. If I upload a 250K image and a medium and thumbnail are created from it the medium may be 120K and thumbnail 35K so easily I do not see any issues with those stats.
There is no such script that exists that you are looking for. We do occassionally do custom work as time permits for a price but right now we are in an active development cycle working on the new PP8.
You have two choices if you have a huge gallery and 94gb is pretty big
1. You can purge old content in the admin area using the purge by date option
2. If you refuse to delete content you have no recourse but to expand hosting.