A featured image in WordPress is the one picture attached to a post or page as its representative image: the theme shows it at the top of the post, in the blog list, in related-post grids, and your SEO plugin hands it to Facebook, LinkedIn and Google when the link is shared. It is set in the Featured image panel in the editor’s right-hand sidebar, not by inserting an image into the content, which is the confusion behind most “why is my image not showing” questions. Below: exactly where to set it, what size it should be, what it is used for, and the five reasons it fails to appear.
Where do you set the featured image?
- Open the post or page in the editor.
- In the right-hand sidebar, make sure the Post (or Page) tab is selected, not Block.
- Scroll to Featured image and click Set featured image.
- Upload a file or pick one from the Media Library. Fill in the Alt text field while you are there.
- Click Set featured image, then Update or Publish.
WordPress.org calls the feature “post thumbnails” in its code, which is why plugin settings sometimes use that name. One image per post; to change it, click Replace or Remove in the same panel.
What is the featured image used for?
| Where it appears | Controlled by | Notes |
|---|---|---|
| Top of the single post | The theme | Some themes show it full width, some in the sidebar, some not at all |
| Blog index, category and archive lists | The theme | This is the thumbnail next to each post title |
| Related posts, recent posts widgets | Theme or plugin | No featured image means a blank box or a placeholder |
| Facebook, LinkedIn, WhatsApp link previews | Your SEO plugin (Yoast, Rank Math) sets it as og:image | Unless you set a different social image on the post |
| Google Discover and image results | Google reads the same og:image and the page | Large images (1200 px or wider) are eligible for Discover |
| RSS feed and email digests | Feed plugins | Often the only image that survives into an email |
The social preview is the one that matters commercially: a shared link with a strong image gets clicked, a link with a grey box does not. If a post shows your avatar or logo when shared, the featured image is missing or the SEO plugin could not read it; one common culprit is an image format the plugin cannot use, such as .avif, which is fixed by re-uploading the same picture as a JPG or WebP.
What size should a WordPress featured image be?
1200 x 630 pixels, JPG or WebP, under 200 KB. That ratio (1.91:1) is what Facebook and LinkedIn crop to, it is wide enough for Google Discover, and most themes display it without cropping. If your theme shows featured images in a square or 4:3 grid, check the theme’s documentation for its crop and compose the image so the subject sits in the centre. The full size guide by image type is in the best image size for a website; the short version for featured images is: never upload the camera original, and keep the subject away from the edges.
WordPress makes its own copies on upload (thumbnail, medium, large and up to 2048 px) and the theme picks the one that fits each spot, so one well-sized upload covers every use.
Why is the featured image not showing?
| Symptom | Cause | Fix |
|---|---|---|
| No Featured image panel in the editor | The theme has not registered post thumbnails, or the panel is hidden | Check the theme supports featured images; in the editor click the three-dot menu, Preferences, General (Panels on older versions), and switch Featured image on |
| Set, but not shown on the post | Theme setting turns it off, or a block theme template has no Post Featured Image block | Theme options, or edit the Single Post template in the Site Editor and add the Post Featured Image block (themes must register post thumbnails for the panel to exist) |
| Shows on the post and in the list, but not when shared | SEO plugin using a different social image, or an unsupported format such as .avif | Set the social image in the post’s Yoast or Rank Math tab, or re-upload as JPG or WebP |
| Shows twice | Theme displays it and you also inserted it in the content | Remove the inline image; keep the featured one |
| Wrong crop | Theme crops to its own ratio | Compose for the centre, or set the theme’s image size option |
The first row is the most common on custom themes. In a block theme, open Appearance, Editor, Templates, Single Posts, and if there is no Post Featured Image block in the template, add one; that block is what displays it.
Featured image or cover block?
Different jobs. The featured image is metadata: one image that the rest of the site and the social networks can find. A Cover block is content: a full-width image with text on top, inside the post body. A post can have both, and on many themes the ideal setup is a featured image for lists and sharing and a Cover block for the visual header, with the theme set not to show the featured image on the single post so it does not appear twice. Whichever you use, add alt text on both, because the on-page SEO checklist counts images with empty alt text as a fault.
Do you need a featured image on every post?
Yes, in practice. A post without one looks broken in the blog list, shares as a blank card, and cannot appear in Google Discover. Set a fallback so nothing slips through: Yoast and Rank Math both have a default social image setting for posts with none, and some themes have a default featured image option. It is a two-minute setting on every WordPress site I build and it is missing on most of the ones I audit; the WordPress design tips for beginners list the other settings in that category.
Frequently asked questions
The one image attached to a post or page as its representative picture. Themes show it at the top of the post and in blog lists, and SEO plugins send it to social networks as the link preview image.
In the editor’s right sidebar under the Post tab, in the Featured image panel. Click Set featured image, choose or upload a file, add alt text and save.
1200 x 630 pixels in JPG or WebP, under 200 KB. That ratio suits social previews and most themes, and it is large enough for Google Discover.
Usually the theme setting hides it on single posts, or a block theme template lacks the Post Featured Image block. Less often the panel is hidden in editor Preferences or the image format is unsupported.
Indirectly. It is the image used in social previews and Google Discover, and its alt text and filename count for image search. A missing one means blank share cards and no Discover eligibility.
The featured image is metadata used by the theme and social networks; a Cover block is an image with text inside the post content. Use the featured image for lists and sharing and a Cover block for a visual header if you want both.
