Fixes #738 Warn the user if we auto-detect a selection close to the size of the visible selection.
Fixes #738 Warn the user if we auto-detect a selection close to the size of the visible selection.

fzzzy/pageshot,mozilla-services/screenshots,mozilla-services/screenshots,mozilla-services/pageshot,mozilla-services/pageshot,fzzzy/pageshot,fzzzy/pageshot,mozilla-services/screenshots,fzzzy/pageshot,mozilla-services/pageshot,mozilla-services/screenshots,mozilla-services/pageshot