1. What
   1. Visual testing (commonly referred to as visual regression testing,) is the automated process of detecting and reviewing visual UI changes
      1. doesn’t replace unit tests, integration tests and so on
         1. https://seesparkbox.com/foundry/design_system_visual_regression_testing
   2. Visual testing is how you ensure that your app appears to the user as you intended
2. Why
   1. visual errors happen frequently
      1. to ensure that no visual defects
   2. to discover visual defects due to modifications to the software
   3. to validate the visual aspects and elements of an application’s user interface
3. How
   1. Exploratory testing
      1. Exploratory Testing. How to Start
         1. https://www.xmind.net/m/U9bj/
   2. to automate the process of comparing visual elements across various screen combinations to uncover visual defects
      1. capturing a collection of screenshots from a user interface and comparing that collection against a baseline of original or reference images
   3. using tools
      1. Galen
         1. http://galenframework.com/
      2. Percy.io
         1. https://percy.io/visual-testing
      3. Chromatic
         1. https://www.chromaticqa.com
      4. Wraith
         1. https://github.com/BBC-News/wraith
      5. https://applitools.com
         1. https://applitools.com
      6. Gemini
         1. https://github.com/bem/gemin
      7. Selenium Visual Diff
         1. https://github.com/kreyssel/selenium2-visualdiff
      8. more tools
         1. Awesome Visual Regression Testin
            1. https://github.com/mojoaxel/awesome-regression-testing#tools-and-frameworks
         2. https://visualregressiontesting.com
         3. https://applitools.com/blog/visual-regression-testing-selenium
         4. https://testguild.com/top-21-free-visual-validation-tools-testers/
         5. https://automated-testing.info/t/17-instrumentov-kotorye-uspeshno-pomogayut-s-avtomatizacziej-visual-software-testing/5670
         6. https://docs.cypress.io/plugins/#visual-testing
4. Where
   1. apps
   2. design system
5. When
   1. as part of your CI/CD pipeline
6. Who
   1. Discovery & Delivery Teams