When someone shares a WordPress post, a social network or messaging app fetches the page and uses information in its HTML to build a preview. The og:image tag gives that service the URL of an image to show. If the tag is missing, the service may choose an image from the page instead, and different platforms can handle that fallback differently.
PressQueue helps WordPress publishers set a social image and, when configured, use that image as the post’s og:image. Knowing how platforms read and cache these tags helps you choose an image and fix a preview that looks wrong.
What og:image tells a link preview crawler
Open Graph is a set of metadata tags that publishers place in a page’s HTML. A crawler is an automated service that visits the page and reads those tags when someone shares its link. The Open Graph protocol defines og:image as the image URL that represents the page in a social preview.
The protocol also defines tags for the page title, type, and canonical URL. Image details can include the image’s dimensions, format, and alternative text. The og:image:alt value should describe what is in the image, rather than act as a caption.
A page can include more than one og:image tag. When those tags conflict, the protocol gives preference to the first image listed in the page’s HTML. In practice, duplicate or competing tags can confuse crawlers, so check that only the intended image appears first.
How a platform chooses the preview image
The crawler first reads the page’s metadata. If the page has an og:image tag, the crawler uses its URL to find the image. Some platforms also read their own image tags. X, for example, has used twitter:image; documentation on X sharing and Twitter Cards describes those tags and their historical fallback relationship with Open Graph tags. Platform behavior changes, so do not assume every service follows the same fallback order.
If the page has no usable image tag, a service may scan the page and select an image it considers suitable. HubSpot’s link preview troubleshooting guidance says the service may use the first image it finds. That fallback is less predictable than setting og:image directly.
The crawler must be able to access the image. Site security rules or robots.txt can block it. For a WordPress post, check the page’s HTML for the actual og:image value and confirm that the image URL loads publicly.
Choose an image that survives cropping
A common starting size for images shared across platforms is 1200 × 630 pixels, an aspect ratio close to 1.91:1. The Open Graph protocol does not require that size, and each platform can crop or display the image differently. Keep the subject and any text away from the edges so a crop does not remove them. The image-size guidance for social previews presents 1200 × 630 pixels as a practical recommendation, rather than a universal platform rule.
Use a clear image that makes sense alongside the page title. If the graphic includes words, keep them brief and large enough to read in a small preview. Add alternative text that describes the image, and verify that the file format and size work for the platforms where the link will appear.
A WordPress featured image and an og:image serve related but distinct purposes. The featured image belongs to the post in WordPress; an SEO plugin or sharing tool can use it as the social image, but the page can specify a different image for link previews. Check the metadata rather than assuming the featured image is the one a crawler will choose.
Why an old or incorrect image still appears
Social platforms cache link previews. After a crawler reads a URL, the platform may keep its title, description, and image for a while. Changing the WordPress image does not refresh every saved preview right away. Each platform has its own cache timing and refresh options.
If a preview is stale, first inspect the page’s current og:image tag and make sure the image URL works. Then use the platform’s preview inspection or refresh tool where one is available. HubSpot also lists duplicate metadata and crawler access as reasons an image may not display as expected.
How PressQueue sets social images
PressQueue is a free, open-source WordPress plugin that shares posts through Buffer. It can use a post’s featured image, an image selected in the post, a social image, or no image for a share. Its social image feature also lets you set the image used in link previews.
To set it up:
- Download pressqueue.zip from the PressQueue download page, then upload it through Plugins > Add Plugin > Upload Plugin in WordPress.
- Connect Buffer by pasting a personal API key from your Buffer settings. PressQueue has no Buffer login button. Its documentation explains the installation and connection steps.
- In Settings > Social images, choose a background or your own image, then set the font, text color, alignment, and site name. PressQueue creates an image using the post title and site name in a wide format suited to link previews.
- In the link-preview settings, choose whether PressQueue should use its social image for every post, only posts without their own image, or no posts. If an image is already set for a post in Yoast SEO, Rank Math, The SEO Framework, or Jetpack, that post-level image takes precedence.
- Keep PressQueue in Test mode while checking what it would share. Test mode records planned shares without sending them. After checking the result, switch to Live when you are ready to share.
PressQueue generates a social image the first time a post needs one and redraws it when the title or image style changes. It requires PHP GD with FreeType to create the image. If the host lacks that support, posts go out with text and a link instead. PressQueue can share through Buffer to LinkedIn, X, Bluesky, Mastodon, Threads and Facebook.