We use a business cloud storage account with version history for exactly this kind of thing, and for a company with years of product photos that is fine.
One warning though: a synced folder is not a backup by itself. Delete or overwrite a photo on one laptop and the same thing happens on every other machine connected to that account.
Versioning lets you get it back, but only if you notice in time and go digging through the history. Nobody checks a product photo from three years ago until they need it.
So keep a second copy somewhere else as well; the cloud account for daily work, the second copy for the day something goes wrong.
