I don't see any extra lines or double images when switching to compatibility mode on your site, however I do have a theory on why the image is displaying on your site and zarzal's but not here.
I think it's possibly to do with XHTML errors. When I do a check here, there are quite a few but all of them are missing alt tags on images. When I run a check on your site and on zarzal's there are all sort of XHTML issues. It very well could be related.
