Capture by Techulus - The ultimate toolkit for converting HTML to image & PDF. Pay only for what you need.No Subscription.
browserling - Live interactive cross-browser testing from your browser.
Screenshot Machine - Screenshot machine is an online website capturing service. Creates a screenshot or thumbnail of any online web page in couple of seconds for free.
BrowserStack - BrowserStack is a software testing platform for developers to comprehensively test websites and mobile applications for quality.
ApiFlash - ApiFlash is a powerful serverless screenshot API built with Chromium and AWS Lambda. It can easily scale to millions of screenshots per day and has an ever growing number of satisfied big clients.
Browsershots - Browsershots makes screenshots of your web design in different browsers.