What is the Fb.ui feed picture size limits?

I'm using the Fb.ui feed and I'm trying to find the picture size limits/requirements. Not all of my images appear 开发者_如何学Pythonusing the feed, and I'd like to know exactly what the image requirements are. This is not well documented.

I'm pretty sure the open graph image rules apply:

An image URL which should represent your object within the graph. The image must be at least 50px by 50px and have a maximum aspect ratio of 3:1. We support PNG, JPEG and GIF formats. You may include multiple og:image tags to associate multiple images with your page.

What is the size of the image you are unable to post?

From my testing, the max size is 320x320. It'll keep your aspect ratio within those bounds.