How to get rid of picture when you type in website

Hi when I type in my http://www.veteransbackingveterans.org I get a picture of a man sitting in a chair. How do I get rid of this picture and put a picture I want for my website to show?
Thank you.

Hi,

I just checking your site but I can’t see the picture that you want to replace. Did you already fix this issue?

Regards,
Awan

When I type my website into f/b it gives the link to my website with a picture of a man sitting down. I am sorry I did not explain it better. I don’t know now if this is just Facebook or it also happens when I throw the website address on another site.

Oh I see…
So its about facebook graph and SEO. You can try to install yoast plugin to manage the SEO