If you open the link https://www.facebook.com/FHFteam
you can then paste the treasury URL into the post box, wait a few seconds for the image to appear, you can then select which thumbnail you want as your picture. Click post.
If your want to tidy up the post further, prior to clicking post, remove the URL from the post box and replace with your own comment, then click post.
FB puts all these posts in the posts by others page as your not admin. I've been resharing to the highlights page (I aim for once a day) to keep the page looking fresh and pretty.
Any problems let me know