User blog comment:BertH/Layout and navigation updates coming October 3/@comment-1435793-20120919225351/@comment-1280533-20120919233853

I had the same problem with background image weight, but I needed the full image anyway as we use transparent content space at Fable Wiki.

The Content Team (or whatever they are called right now) were very helpful, and managed to optimize the image to get its file size down from 215 to 149. There's no obvious reduction in image quality, and as an added bonus, they gave the image fade-to-black edges as well, for those people who have really large monitors.

Alternatively, you can upload the image directly to the wiki with Special:Upload and pull it for the background with CSS.