In my setup, it creates the PNG snapshots and compares them to the snapshots stored in Git at each test run. In result, I get the number of different pixels and the test fails if the nunmber is higher than 0. It also produces a visual PNG diff file, that has 3 panes: expected, actual, diff heatmap. The setup took just few hours.
However there are some screen resolution limitations in Cypress right now. I could not get it to work in resolution higher than 1200x1024. More about that problem: https://github.com/cypress-io/cypress/issues/2102
I'd encourage you to try Git LFS, it's a very simple extension to Git. It only takes a couple of minutes to set up if you use GitHub, and I suspect other platforms are similar :)
