Use browserstack to test your application in all browsers without having to install each one, including mobile browsers, different phones, tablets, etc.
There is support for Selenium automated testing and screenshots. Local testing is supported, no public URL is needed.
The screenshots API is available for configuring the screenshots you need, Screenshooter is a a tool for generating BrowserStack screenshots from the command line.
There is a trial period for this as it's a commercial product, but it's very well made and worth every penny. You can subscribe for only one month. I have used personally and I highly recommend it.
