If you’ve got the latests Google Photos, which chances are you do, you’ve got a chance (albeit slim,) that you now can, or soon will be able to colorize black and white photos.
The colorization is done server side using AI and beads on sticks containing magic, so there’s nothing you can do other than update your Google Photos and do what we’re doing, wait.
Once you’ve waited and all of your friends have the colorize option and you’re feeling sufficiently left out, Google will roll the feature to your Google Photos and you’ll be able to colorize all your grandparent’s photos, or any stylized monochrome ones.
In the meantime, you can search for “black and white” photos in your Google Photos to see if there’s anything you’re particularly interested in colorizing.
Once the feature is available there will be an option to colorize when you’re editing any photos. The colorization looks a little like early movie colorization, in that it’s good but everything’s just a little subdued.
Considering the web Photos and the App are pretty much hand in hand these days I’d expect that once Google flips the switch for you both app and web will colorize, but who knows.
You can see some colorized photos that got monochromed and then re-colorized by AI over at 9to5Google.