Chrome css image holder maxwidth

The max width of IMG tags in Chrome 22 breaks at widths greater than 35791394px. This affects other (older) Webkit browsers (late 2012), but was fixed in [December 2012](https://bugs.webkit.org/show_bug.cgi?id=102735). In certain environments (say, in an office or school), the browser might not always be up to date, and so this fix addresses these older browsers. Specifically, this affects the ``width``, ``height``, ``left`` and ``top`` properties.

I've modified ``screen.css`` as a workaround for older Webkit-based browsers that have this issue.