Apologies if this isn't the right place to post this, please direct me to the proper place if it isn't:
I have everything built out pretty good in the flow, and it triggers and passes every test, but I'd like to make the alert email that goes out look a alittle nicer, and closer to the "send by email" option that is offered on the SharePoint site itself (pictured below).

However I've not been able to replicate the thumbnail to show for the preview of the post, I have a few properties pulled from dynamic content like "thumbnail large, medium and Small" but they always return as if they don't exist so i'm not sure what they do.
Does anyone have any ideas on how i can complete this using my flow I have built?