The icons in the upper-left and lower-right corners of the screen are the collapsed header and footer. The gray line at the left edge of the screen is the collapsed sidebar. Mouse over them to restore the element.

A http://forum.userstyles.org/discussion/37261/bug-ish-background-is-oddly-misaligned-in-the-automatic-screenshot (#5).
09-11 create style; "Automatically generate screenshot" with "Example URL" ([http://www.valuewalk.com/2013/09/apple-inc-aapl-downgrade/])
09-28 site adds http://cdn.userstyles.org/auto_style_screenshots/92878-after.png but doesn't display it: "No changes found after style was applied."
          N.B. Site's screenshot is oversized (115,654b).
09-29 "Use this screenshot"; using site's (undisplayed) 09-28 screenshotN.B. Warning is now gone from site's screenshot.