Do not attempt browser image decoding if the browser does not have the window.URL or window.webkitURL objects. Fix the warning print to appear in that case on Opera/9.80 (Windows NT 6.1; WOW64) Presto/2.12.388 Version/12.16.
Merge pull request #1484 from juj/browser_image_decoding_check

Fix --preload-file on image files on Opera.