> The main tricky bit is making sure you're snapshotting/backing up everything frequently.

Yeah this can be crappy.

> SaaS products

There's managed postgres on aws, ovh, heroku, digital ocean, vultr, fly.io

optimism

There's a wide range of options here, but if

I'd recommend storing text fields in an embedded sqlite database and storing images on a colocated SSD. The main tricky bit is making sure you're snapshotting/backing up everything frequently.

If you're cobbling together SaaS products, I'm not familiar with those, personally.

What is another good backend data storage application?

PictureRoom

There's a wide range of options here, but if 

1. you're comfortable hosting the server on a VPS
2. want to keep costs low and portable
3. don't anticipate needing massive scale

I'd recommend storing text fields in an embedded sqlite database and storing images on a colocated SSD. The main tricky bit is making sure you're snapshotting/backing up everything frequently.

If you're cobbling together SaaS products, I'm not familiar with those, personally.