It's tightly integrated with it, so if not "only for Storybook," then near to it. I like Storybook, but it's not worth implementing solely for visual CI testing IMO.

But phrases like "snapshot testing" and "visual regression testing" are what you you/your FE team should be Googling – hopefully there's a tool out there that fits your existing architecture!

Otherwise, as sibling commenters have noted, a policy of screenshots also works.