When adding/editing a page, you can change the default width and height of the capture under the Advanced Settings.
Width
You can specify a width (in px) that will be used as the browser viewport width when capturing that page.
This means that you can capture desktop versions of a webpage by setting the width to 1280px or more.
To capture mobile versions of a page, set the width to around 375px. To capture tablet versions, set the width to around 760px.
Mobile Viewport
In some cases, just setting a smaller width might not get you the mobile version of a webpage. If that happens, set the Mobile Viewport option to Yes as well.
Full Height
By default, the Full Height option is enabled and thus the full height of the webpage (with all of this content) will be captured in the screenshot (usually up to 10,000px). In this case, the specified Height value is ignored.
Height
But if you disable Full Height, then the height of the screenshot will be whatever you specify in the Height field (in px).
