Facebook publish post with link and big image

Question

I use Koala to publish a post with link to a Facebook Group

@graph = Koala::Facebook::API.new(access_token)

@graph.put_connections(group_id, "feed", {
              :message   => post_message,
              :picture   => backdrop,
              :link      => url
            })

I get this post

Instead I have to do this

Answer 1

According to the FAQ of this document Image Optimization for Link Page Posts.

What is the minimum image size required to generate a link share post with a large image?

600 x 315px is the minimum size that we require. However, we recommend that you use images that are at least 1200 x 630px for the best display on retina and high-resolution screens.

What will happen if the image is below the minimum requirements?

If the image is smaller than 600 x 315px, we will render it at 154 x 154px or smaller on mobile or desktop.