Open Graph Image: some work and some don't

Hello – I am having trouble with our sites open graph images on both the main landing pages and the insight pages. Some are working…some aren’t. I can’t figure out why some show but others don’t.

For main pages:
We have added the image URL in the page settings. Only 5/12 pull through when you post the URL in LinkedIn/Slack/etc. The pages that work are:

  1. What We Do
  2. DevOps
  3. Continuous Delivery
  4. Career Opportunities
  5. Insights

The pages that don’t have an Open Graph Image pulling through:

  1. Home Page
  2. Software Design & Development
  3. Cloud Engineering
  4. Who We Are
  5. Security by Design
  6. Life at Trility
  7. Veterans

For insight (blog) pages:
We added thumbnail and main images for all blog posts. In the Insights template settings, we told the open graph image to pull from the main image. Some pull through and some don’t. There are over 100 blogs so I won’t list these out but can go into more detail if needed.

Can anyone tell me:

  1. Why only some open graph images pull through?
  2. How to get all to pull through?
  3. Best practices for how to upload, compress, and leverage images throughout the site? (EX: Should we always start by putting images in the asset manager? Should we add alt text here? What dimensions would be considered a best practice? Etc.)

Thanks in advance!

Here is my site Read-Only: