Here is a little gotcha I discovered today with Yoast and the og:image Facebook tag not working
I wanted to specify the og:image file used for the homepage of a site as Facebook was pulling one of the recent posts images from the homepage. Luckily Yoast SEO allows you to specify an image for the OG Image tag on a per-page basis.
So I uploaded a PNG image file for the homepage, then ran the Facebook Debugger, fetching new scrape informaiton to make sure it wasn’t providing cached results and it was still picking up on recent posts images that appeared on the homepage.
Trying a jpg file solved the problem, so it appears that Facebook has a hard time working with PNG image files for the og:image tag? This is odd as I looked at some other sites with png files for og:image and they appeared to load fine.