Then I save "width" x "height" screenshot

Resize the viewport to <width> x <height> then save a screenshot.

Then (I |we )*save (\d+) x (\d+) screenshot

Example #1: Then I save 1440 x 900 screenshot
Example #2: Then we save 1200 x 800 screenshot

Example #3:

 Given I am on "/about-us"
  Then I save 1440 x 900 screenshot