Here's what I do. First, the markup:
<time datetime="2011-08-27T19:15:38Z" pubdate>27 Aug, 2011</time>
So, time in [ISO 8601][0] format. Run JS to transform '27 Aug, 2011' into a relative date.
If the relative date is >1 month (or, whatever you'd like), then just display the full date.
Ding ding ding. Machine readable and user-friendly.
If you're making your users' experience worse out of a fear of breaking the relative value of screenshots you might need to re-examine your priorities.
This would even let users change the date back with a user script.
A browser/extensions could add a tooltip or context menu item to time elements, showing relative and absolute dates regardless of the way it's authored.
[0]: http://en.wikipedia.org/wiki/ISO_8601