diberry - 12:57 am on Apr 19, 2013 (gmt 0)
Backdraft, I don't think it's that your domain is EMD. I think it's that it's EMD *and* your use of those words in your navigation structure. It may be Google's changed something about how it weighs EMDs, and suddenly what's been fine all these years looks like overoptimization.
If netmeg's had experience where changing the anchor text in the navigation helped this type of penalty, I'd think it's worth a try. Removing the EMD words from your navigation links ("widget" in your example above) should be a pretty quick and easy fix.
As for the slider images, I don't know how Google looks at image meta. But sliders can slow down a page load, and that might count against you - somewhat. I don't remotely think that alone would account for your penalty, but I'd check Pagespeed to see what it says about your site speed. I don't go batty trying to score 100, but sometimes Pagespeed reveals a simple change I could make with an hour's work that will bring it up 5 points or so, and I figure those changes are always worth making.