Facebook没有显示正确的共享图像

Question

示例网址：http://metalmouth.net/2014/07/algebra-feed-the-ego-streaming-in-full-from-swiss-thrashers/?w3tc_note=pgcache_purge_post

FB调试器：https://developers.facebook.com/tools/debug/og/object?q=http%3A%2F%2Fwww.metalmouth.net%2F2014%2F07%2Falgebra-feed-the-ego-streaming-in-full-from-swiss-thrashers%3Ffbrefresh%3D1

当我在网站上分享文章时，它会显示FB调试器页面中提到的图像。但是，即使调试器页面上的共享预览显示正确的图像！

调试器说：

og:image could not be downloaded or is too small    

Provided og:image could not be downloaded or is not big enough. Please use an image that's at least 200x200px and is accessible from Facebook. Image 'http://www.metalmouth.net/media/2014/02/klogr-300-banner-MetalMouth.gif' will be used instead.

问题是，图像尺寸远远超过200x200 - http://www.metalmouth.net/media/2014/07/algebra-band-2014-500x437.jpg

这只是FB的另一个功能吗？