XF 1.5 Xenforo Logo on Facebook

I changed to Xenforo logo to a custom logo for my Forum

Whenever I post a link on Facebook I still get the Xenforo
Logo showing up instead of my logo

any ideas?

@Ernest L. Defoe I did

this is my logo

but its showing up on facebook like this

Can I use the same image path as the main logo? I am not sure, it is now showing the avatar image of the person who posted the thread. I am assuming I can change this to our logo? Thank you,