Gallery Update Across Network

I manage a network of 27 sites for a large non-profit. Each of these sites has a 4 image slider on the homepage that changes on a regular basis.

At the moment, I have to go into each of the 27 sites and change the images & links every time there’s an update.

Is there a way to create a slider that can be used across the network, so that I only have to udpate the 1?