Blitapp can log in to a website and take screenshots of multiple pages. We have an example on our blog that describe this process using the initial automation steps.
In a nutshell, you can describe what field to fill in (username, password), click the login button, and wait for the login to happen.
In your capture, list all the URLs that you want to capture after the login form:
Our customers use this feature to capture dashboards, share internal stats with their customers, and more.