Additional useful info:
You can provide several og:images, whatsapp will use the last one. This will help with the problem that e.g. facebook want 1.91:1 ratio and whatsapp 1:1
<meta property="og:image" content="https://www.link.com/facebook.png" />
<meta property="og:image:type" content="image/png" />
<meta property="og:image:width" content="1200" />
<meta property="og:image:height" content="630" />
<meta property="og:image" content="https://www.link.com/whatsapp.png" />
<meta property="og:image:type" content="image/png" />
<meta property="og:image:width" content="400" />
<meta property="og:image:height" content="400" />
https://roei.stream/2018/11/18/ideal-open-graph-image-size-for-whatsapp-link-share/