7.1 Blog Thumbnail as background image

Hi there – wondering if there is anyway to have the thumbnail that is uploaded to a blog post to display inside the blog in addiction to the grid page. 

Specifically looking to get it left aligned and take up 50% of the screen.

site: https://tarantula-calliope-fl4m.squarespace.com/blogs/knowledge-base

pass: squarespace

current code – clearly not looking to have the same image on every blog so I'm looking for someone to replace the url with a thumbnail target...

/* Blog Interior */
.blog-item-wrapper article.entry {
  padding-top: 0;
  padding-bottom: 0;
  background-image: url("https://static1.squarespace.com/static/5eb179d00c6aef0b9ed1bfaf/5eb29c388099026de92ca571/5ec9945e02f4af1d185a2ed1/1590287286817/usual_wines_temperature_1024x1024.jpeg");
  background-repeat: no-repeat;
background-size: 50%;
}

I was able to fine a great article by: https://www.will-myers.com/articles/adding-a-banner-image-to-a-blog-in-squarespace-71

it looks like in javascript you can target 

property="og:image"

to pull the thumbnail, but I'm lost on how to get it to the left side vs. top. If there are any java folks out there, would love some help!!