Support parsing image alt text

[aciccarello]

Open Graph Protocol images can include alt text. Metaformats should include parsing this content to ensure maximum accessibility.

OGP Example

<meta property="og:image" content="https://example.com/ogp.jpg" />
<meta property="og:image:secure_url" content="https://secure.example.com/ogp.jpg" />
<meta property="og:image:type" content="image/jpeg" />
<meta property="og:image:width" content="400" />
<meta property="og:image:height" content="300" />
<meta property="og:image:alt" content="A shiny red apple with a bite taken out" />

Real world example

The Verge Article

<meta property="og:image" content="https://cdn.vox-cdn.com/thumbor/QCdO_oKAdBIZCodEUT2WCBFgQSo=/0x0:2040x1360/1200x628/filters:focal(1020x680:1021x681)/cdn.vox-cdn.com/uploads/chorus_asset/file/24390406/STK149_AI_03.jpg">
<meta property="og:image:alt" content="A rendition of OpenAI’s logo, which looks like a stylized whirlpool.">

It's worth noting that some tools/sites have intentionally not included og:image:alt due to poor usage. The Yoast Blog has a good explainer.