How or where can I edit the open graph markup that appears when i include a link to my website in comments on fb groups etc. Since my first image on my website is a white png the image that shows is not good... plus it grabs a random sentence that looks pretty negative when singled outside of the context it was written on in the site. Doesn't give me a very good look when trying to drum up business... see you can see the sentence it pulls up makes it look like im advertising my website is boring and outdated... but as a website designer that is what I am helping them with.
Attached files: Screenshot 2017-09-05 13.15.11.png
This is plugin territory, try an SEO plugin such as Yoast SEO which also provides options for Open Graph tags.