Sauce Labs uses official Selenium WebDriver releases for all our browsers. In Selenium, each browser's WebDriver implementation handles screenshots differently, in a way specific to the browser. Screenshots generally work as expected in Firefox, but there are currently known issues with Selenium's screenshot capturing capability for Internet Explorer, Chrome, and Safari drivers.
Internet Explorer WebDriver screenshots will sometimes have black bars on the image. However, you can solve this problem for Internet Explorer on Windows 7 and up! The issue is related to 32/64 bit systems, and Sauce is proud to offer support for the 64-bit Internet Explorer WebDriver, which takes perfect full page screenshots (except for IE9, see below). To use it, set this desired capability in your test:
For Windows 7 with IE 9, note that the 64-bit driver is currently incompatible with this combination, but the regular 32-bit driver does take full page screenshots.
Chrome WebDriver screenshots capture part of the page. This is a known Selenium issue, and Sauce Labs looks forward to a fix. https://code.google.com/p/chromedriver/issues/detail?id=294
Safari WebDriver screenshots also capture part of the page. This is a known issue as well: https://code.google.com/p/selenium/issues/detail?id=3752