I really don't want to pay a monthly subscription (FOREVER) in order to safely and privately backup these photos etc. But are there other options?
Define "safe"? :)
How many backups of the data do you have now (are you resilient to the copy becoming corrupted on Drop Box, for example?), and what are you trying to protect against (presumably theft or house fire, among other things?)
Maybe just a thumb drive and a safe deposit box? I have pictures of my house and stuff for insurance purposes, on thumb drives. Even good ones are silly cheap per GB and they are likely to be even more so in the next 60 days. Now I turn those pictures over every year or two, so I don't bother to do additional backup of those particular pictures.
For other pictures which I'm trying to have survive, I have multiple copies, on multiple devices, and those copies are also supplemented with par2 (see
https://en.wikipedia.org/wiki/Parchive).
...but even then, you are taking on the burden of ensuring the systems on which you store the data don't become bad/obsolete/etc. Part of the monthly subscription is because they are doing that conversion of hardware in the background. So far I've done DIY (mainly because the volume of what I'm backing up and it's true life significance isn't that huge in the grand scheme)