(feat) Comparing screenshots from the same test run

[Tobio89]

Describe the solution you'd like

I am looking for a way to take screenshots of the app and compare them.
The app I am testing uses HTML Canvas. I'm looking for a way to achieve this process:

1 - Take a screenshot, saved under a name
2 - Make a change to the UI
3 - Take a new screenshot
4 - Compare the first and second screenshots to see if the change actually happened.

Looking at the docs, I couldn't see if this feature already exists. If it does, that would be great!