A bit of an update for anyone dealing with this mid-2019. I was dealing with this today. I was trying to specify a certain thumbnail to be shown in the rich message preview across Facebook messenger, iOS messages and android messages.
Using actual code from the website I was working on. Be sure to replace content with your own.
These 4 tags made it work for me on Facebook messenger and iOS messages:
<meta property="og:title" content="Software to manage leasing and rental applications" />
<meta property="og:type" content="website" />
<meta property="og:url" content="https://geteagle.com.au/products/leasing-tools/" />
<meta property="og:image" itemprop="image" content="https://geteagle.com.au/site/templates/images/logo-og-white-big.jpg" />
For some reason, android messages refused to show the thumbnail I specified. I did a lot of research and tried everything I could find in this other question: Showing Thumbnail for link in WhatsApp || og:image meta-tag doesn't work
My tags bloated to 9 (8 meta, 1 link), but it was actually the link tag that made it work in android messages:
<link itemprop="thumbnailUrl" href="https://geteagle.com.au/site/templates/images/logo-og-white-big.jpg">
I'm not sure if the other tags are needed in addition to the link tag to make it work on android messages, but here is the full block if you want to try:
<meta property="og:title" content="Software to manage leasing and rental applications" />
<meta property=”og:description” content="Eagle offers a suite of of leasing tools and application management features to power-up your rental team!" />
<meta property="og:type" content="website" />
<meta property="og:url" content="https://geteagle.com.au/products/leasing-tools/" />
<meta property="og:image" itemprop="image" content="https://geteagle.com.au/site/templates/images/logo-og-white-big.jpg" />
<meta property="og:image:secure_url" itemprop="image" content="https://geteagle.com.au/site/templates/images/logo-og-white-big.jpg" />
<meta property="og:image:width" content="1000" />
<meta property="og:image:height" content="500" />
<link itemprop="thumbnailUrl" href="https://geteagle.com.au/site/templates/images/logo-og-white-big.jpg">
Many thanks to this particular answer from the question mentioned above that resolved my frustrating situation.
Hope this helps. Good luck!