I made the sharable OpenGraph images on this site better by generating custom cards contextual to each post:

The core concept is to create a sidecar page for each post that looks like an OpenGraph card, then take a snapshot of the page, and set it as the og:image meta tag on the original post.

There are a few Gatsby plugins that attempt to help, but they rely on Puppeteer to generate screenshots at build-time, which can slow down a build pretty significantly, and adds a heavy dependency to the toolchain.

The approach I took leverages Gatsby's dynamic page generation, but leaves the image rendering to external services, only generating as-needed at runtime.

You can view the generated card for this post to get a feel for what's getting generated, and see a full implementation diff here.

React Card Component

Like other Gatsby pages, this is a React component you'll set props via Gatsby. I placed it in components/social-card.js. Since OpenGraph images are generally a fixed size, you can target your design for those specific dimensions.

import React from 'react';

// It's a Gatsby component, so pull in whatever assets are useful for the page
import avatar from '../../content/images/avatar-transparent.png';

// I'm using CSS Modules for styles, but you do you
import { card, cardTitle, cardExcerpt, cardDate, cardMetadata, cardAuthor, cardAvatar, cardTransparency } from './social-card.module.css';

const SocialCard = ({ pageContext: { title, excerpt, date } }) => {
  return (
    <main className={card}>
      <h1 className={cardTitle}>{title}</h1>
      <p className={cardExcerpt}>{excerpt}</p>
      <img className={cardAvatar} src={avatar} alt="Avatar" />
      <div className={[cardMetadata, cardTransparency].join(' ')}>
        <p className={cardDate}>{date}</p>
        <p className={cardAuthor}>steele.blue</p>
      </div>
    </main>
  );
};

export default SocialCard;

Gatsby Card Pages

In gatsby-node.js, enhance the onCreateNode method (or wherever you're currently calling createPage) to generate a new page, which will be for your component's social card.

First, query for all blog posts, pulling the props you'll want:

  // Query for all blog posts
const socialCardQuery = await graphql(`
{
  allMarkdownRemark {
    nodes {
      excerpt
      fields {
        slug
        date(formatString: "MMM DD")
      }
      frontmatter {
        title
      }
    }
  }
}
`).then((res) => res.data);

Then create a Social Card page for each post, passing in the relevant props:

const pageContexts = socialCardQuery.allMarkdownRemark.nodes.map((node) => {
  return {
    slug: node.fields.slug,
    pageContext: {
      title: node.frontmatter.title,
      excerpt: node.excerpt,
      date: node.fields.date,
    },
  };
});

const socialCard = path.resolve('src/components/social-card.js');
pageContexts.forEach((page) => {
createPage({
    component: socialCard,
    path: `${page.slug}/social-card`,
    context: {
    ...page.pageContext,
    },
});
});

Once these are getting generated, you can just add /social-card to the end of any permalink to see what's getting generated, and iterate until you're happy.

OpenGraph Screenshots via 11ty API

Ultimately OpenGraph expects an image, and we currently have a website. Fortunately for us, the Eleventy project supports a service that will generate screenshots of pages via URLs, with presets for OpenGraph dimensions.

In your blog posts, you'll want to define the og:image meta tag based on these properties. Here I'm using React Helmet, but you could also do it with the Gatsby Head API.

// Helper methods to configure the Eleventy Screenshot Service
const socialCardUrl = (url) => `${url}/social-card/`;
const screenshotUrl = (uri) => {
  const encoded = encodeURIComponent(socialCardUrl(uri));
  
  // https://github.com/11ty/api-screenshot/#manual-cache-busting
  const cacheBust = new Date().getTime();
  return `https://v1.screenshot.11ty.dev/${encoded}/opengraph/_${cacheBust}`;
};

// Then in your blog post's component, set the value:
<Helmet
  meta={[
    {
    property: 'og:image',
    content: screenshotUrl(url),
    },
    // etc
  ]}
/>

And with that, you're off to the races! As Zach put it, perhaps folks will start clicking on my posts if I work really hard on the OpenGraph images.