Answer:
All screenshots are captured using Headless Google Chrome running at a 1920x1080 resolution.
If an element or region is set to be captured, this is captured at the native resolution of the element or region, for example, if you choose to capture a 200x400 pixel zone of the URL, the resulting image will also have a 200x400 pixel resolution.
If the element or zone chosen extends past the 1920x1080 resolution, the zone/element will be scaled down in resolution.