Share image on social media

[titipata]

Now, when I share the page on social media, it will pop up with hero image. It would be nice if it pops stack blog image up instead (I tried to find one but images folder is pretty big). I think we can change og tag in _layouts/default.html where right now is
<meta property="og:image" content="{{ page.hero }}"/> to if-else statement, something like this,

<meta property="og:image" content="{% if page.layout=='post' %} {{page.hero}} {% else %} {{path_to_default_image}} "/>