Clear and concise description of the problem

There is no built-in way to compare images in the browser mode.

Suggested solution

Implement a snapshot-style assertion to compare previously stored images. I am open to API ideas.

This issue is opened to start a discussion around the topic.

Alternative

Related: #690

Additional context

Consider using https://github.com/mapbox/pixelmatch as it is small and fast

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.