I should add, really, I was looking for solving the Cucumber/Appium/iOS/Safari equation. Test Automation, ftw!: OS X Setup and iOS Device Configuration for Mobile Web Test Automation Using Free iOS Provisioning Profile hopefully does the job.
This chapter would help you understand how to execute the test on real Android Devices, after all the biggest advantage of Appium is that you can run the same test on local devices.
There’s a PR that would allow to feed it a cookie. Now add a better way to limit the crawling scope and it’s damn interesting!
A nice overview of articles on Visual Regression Testing.