Default Image when sharing a post > facebook

Hi

goal: to have all my blog posts that are shared to facebook use our logo

I’ve downloaded the functionality plugin / insert the code from here: http://jetpack.me/2013/10/15/add-a-default-fallback-image-if-no-image/

dropped my image url (H and W are larger than 200px) in between the single quotes ‘YOUR_LOGO_IMG_URL’

but when I try to share, it’s still giving me 3 random pictures to use, not my logo

any suggestions?

https://wordpress.org/plugins/jetpack/