The WordPress featured image is one of the basics you come across when you write your first page or post. Yet when you are starting out, it is anything but obvious: there is no real equivalent on other platforms, its location in the editor has moved over the versions, and the way it looks on your site depends almost entirely on your theme.
Also called Post Thumbnail or main image, it is a theme feature that arrived with WordPress 2.9 (yes, that was a while ago!). Its role is to represent the subject of the post. Even if a post contains ten photos, the featured image is the one displayed on the home page, on category pages, in recent posts blocks and, very often, when the post is shared on social networks or shown in Google Discover.
This guide covers everything in the order you will need it: how to add the image, replace or remove it, what to do when it does not show up, what changes between a classic theme and a block theme, and then best practices for dimensions, performance, accessibility and visibility.
This guide is the English version of an article first published in French in June 2016 and updated on October 8, 2026. The update covers the procedure in the block editor, the replace, remove and troubleshooting sections, the difference between classic themes and block themes, recommendations on dimensions, performance, accessibility and Google Discover, the maintenance status of the plugins mentioned (checked on WordPress.org) and an FAQ.
How to add a featured image in WordPress
The steps differ slightly depending on the editor you use. In both cases, the chosen image is saved with the post or page when you click Publish or Update.
With the block editor
- Open the post or page, then display the settings sidebar on the right of the screen (the Settings icon at the top right if it is closed).
- Click the Post tab (or Page, or the name of your content type), not the Block tab.
- Find the Featured image area. Depending on your WordPress version, it sits at the top of the tab or further down the sidebar: scroll if you do not see it straight away.
- Click Set featured image to open the Media Library, or drag an image from your computer straight into the grey area.
- Select the image, confirm, then save your post.
It takes a little getting used to, and you may need a few seconds to find it the first times. After that, it becomes second nature! If you are new to this editor, here are good reasons to use Gutenberg WordPress blocks.
With the classic editor
If you have chosen to keep the old WordPress editor, the featured image appears as a dedicated box in the sidebar of the editing screen, below the Publish, Categories and Tags boxes. Just click the Set featured image link, choose the image in the Media Library, then update the post.
If your post contains several images, use this box for the one that best represents your content: the one that best symbolises the subject or illustrates the point, because it is the one your visitors will see first.
Replace or remove a featured image
In the block editor, once the image is set, the Featured image area shows a preview and offers two actions: Replace, which reopens the Media Library so you can pick another one, and Remove, which leaves the post without an image. In the classic editor, clicking the preview lets you change the image, and a link below the preview removes it from the post.
Two useful details. First, the change only takes effect once you have updated the post. Second, removing the featured image only detaches it from the post: the file stays in your Media Library and in any other content that uses it. To actually delete it, go through the Media Library.
The featured image does not show up: what to check
This is by far the most frequent question. There are actually two quite different situations: either the area does not exist in the editor, or the image is set but stays invisible (or displays badly) on the site.
The Featured image area is missing from the editor
- The theme does not declare the feature. The featured image is a theme feature: the theme has to declare it for the interface to appear on the editing screen. This is rare with current themes, more common with old or very minimalist ones.
- The content type does not support it. On a custom post type (portfolio items, events, job offers…), thumbnail support has to be enabled when the post type is registered, in addition to theme support.
- The panel has been hidden. In the block editor, the three-dot menu at the top right gives access to Preferences, where you choose which panels appear in the settings sidebar. In the classic editor, Screen Options at the top of the page does the same job.
The image is set but does not appear on the site
- The theme or template does not display it in that spot. Some themes let you hide the image on single posts, or depending on the device (desktop, tablet, mobile). With a block theme, the template in use must contain the Post Featured Image block (see below).
- The cache has not been cleared. If you use a caching plugin or your host’s cache, purge it before concluding that it does not work.
- The image appears twice. Your theme already displays the featured image at the top of the post and you also inserted it at the beginning of the content. Remove one of them.
- The image is cropped or distorted. The theme enforces a format (an aspect ratio) and crops whatever does not fit. See the section on dimensions below.
- The image is blurry. The uploaded file is smaller than the space where the theme displays it. A small image that gets enlarged never becomes sharper: you need to start again from a larger file.
If the problem persists after all that, it usually comes from the theme code or a conflict with a plugin. That is typically the kind of issue I fix as a freelance WordPress webmaster.
Classic theme or block theme: who decides how it is displayed?
WordPress only records which image is attached to which post. Everything else is decided by the theme: where the image is displayed, its size, its format, and what happens when you click it. The way to change these behaviours is not the same at all depending on the type of theme.
With a classic theme
In a classic theme, the display is written in the theme’s PHP files and, when the author has planned for it, can be adjusted in the Customizer. On this blog, for example, the Blocksy theme offers a Featured Image element for posts, with settings for the aspect ratio, the image size loaded, the width (aligned with the content or wider) and visibility per device. Other themes offer no settings at all: you then have to use a child theme and edit the code.
Depending on the layout chosen, the same image will end up in a grid, a list or full width above the post. Here are two display examples from SoloPine themes, which I used for a long time, first as a grid and then as a list:
The link placed on the image also varies from one theme to another, and it is worth testing on the demo before adopting a theme:
- most often, clicking the image on a home or category page leads to the post: this is what visitors expect;
- some themes display the image without any link;
- more rarely, and not very useful, the image links to the image file itself, in other words a page with no content at all.
With a block theme
With a block theme, the featured image becomes a block like any other: the Post Featured Image block. You place it in templates from the Site Editor, or inside a Query Loop block to build a list of posts. To insert it quickly, type a forward slash in an empty paragraph followed by the name of the block.
What used to require editing PHP can now be set in the block settings sidebar:
- the link to the post: an option makes the image clickable, with the possibility of opening the link in a new tab;
- the aspect ratio, height and width, to keep a grid consistent even when your original images have different formats;
- a colour overlay with opacity adjustable from 0 to 100, handy for placing a readable title on top;
- a duotone filter, a border and rounded corners;
- the alignment, wide or full width.
Another option: the Cover block can use the post’s featured image as its background image, which lets you build a post header with the title on top of the image.
What size should a featured image be?
There is no universal size: the right size is the one your theme displays, with some margin. To understand why, you need to know that every time you upload an image, WordPress generates several versions of it:
- thumbnail: 150 x 150 pixels maximum;
- medium: 300 x 300 pixels maximum;
- medium large: 768 pixels wide, with no height limit;
- large: 1024 x 1024 pixels maximum;
- full size: the file exactly as you uploaded it.
These default values can be changed in Settings, then Media, and themes very often add their own sizes, sometimes cropped. The theme then picks the version that suits each location.
In practice, I recommend uploading an image at least 1200 pixels wide, in landscape format. That is enough for the vast majority of themes, it matches what Google asks for Discover (see below), and WordPress takes care of producing the smaller versions.
Watch out for portrait photos and other images designed for Pinterest: if your theme crops featured images, you may end up with a face cut off at the nose, or a subject sliced in half. Be just as careful with themes that build a large slider from featured images: an image that is too small will look pixelated there.
Finally, after a theme change, your existing images do not yet exist in the sizes the new theme expects. You then need to regenerate the thumbnails, with a plugin such as Regenerate Thumbnails or Force Regenerate Thumbnails. When I checked in October 2026, the WordPress.org page for Regenerate Thumbnails showed a plugin not tested with the last three major WordPress releases, whereas Force Regenerate Thumbnails had received an update in February 2026: make a backup before running the process.
Weight and performance: an image that affects loading time
On a post, the featured image is often the largest element visible when the page opens. It therefore has a direct impact on display speed and on your Core Web Vitals. The good news is that WordPress already does part of the work:
- it gives the browser the list of available versions of the image, so the browser downloads the one that suits the screen size;
- it defers the loading of images further down the page (lazy loading);
- since WordPress 6.3, it tells the browser to load first the image most likely to be the largest visible element, and does not apply lazy loading to it.
What is left for you to do:
- Never lazy load the image at the top of the page. Google is very clear on this: it needlessly delays display. If an optimisation plugin applies lazy loading to all your images, exclude the featured image displayed at the top of posts.
- Resize before uploading. There is no point uploading a 6000-pixel-wide file straight from your camera: reduce the size of the image first.
- Compress and choose a modern format. WebP and AVIF are much lighter than JPEG. WordPress has supported AVIF since version 6.5, provided your hosting supports it: you can check this in Tools, Site Health, Info tab, in the section dedicated to media handling. You can also convert your images to WebP automatically with Tinify.
Accessibility: the featured image alt text
The editor does not ask for alternative text when you set the featured image, so it is very often forgotten. Yet WordPress takes this text from the Alternative Text field of the image, in the Media Library. If it is empty, the image will be displayed without a description for screen readers and search engines.
What should you write in it? The W3C recommendations come down to three cases:
- the image conveys information: describe it briefly, rendering what it means in context;
- the image is a link, as in a list of posts where it leads to the post: the alt text must make the link destination clear;
- the image is purely decorative: the alt text stays empty.
In every case, avoid stuffing it with keywords.
The featured image does not stay on your site. SEO plugins generally use it to fill in the og:image tag, the one Facebook, LinkedIn or X read to generate the preview of a shared link. That is the case on this blog with Yoast SEO. The direct consequence: if you deliberately choose a very small image to suit your theme, say 250 x 300 pixels, that is the version that will be pushed to social networks, where it will be enlarged and look poor.
For Google Discover, Google’s documentation is precise. To have a chance of appearing with a large image, you need:
- an image at least 1200 pixels wide;
- a high resolution, meaning more than 300,000 pixels in total;
- a 16:9 aspect ratio;
- the max-image-preview:large setting enabled on the site (Yoast SEO adds it by default on this blog);
- a relevant image that represents the page: Google asks you to avoid generic images such as the site logo.
None of this guarantees a place in Discover, but it is a prerequisite.
Managing featured images in bulk: useful plugins
When a site has hundreds of posts, or after a migration, handling images one by one is not realistic. Here are the plugins I have mentioned on this blog, with their status on WordPress.org when I checked in October 2026.
See and edit images from the posts list
For content-heavy sites, showing the featured image in the dashboard posts list lets you spot at a glance the posts that do not have one:
Featured Image Admin Thumb (over 20,000 active installations, tested up to WordPress 7.0) adds this column. WEN Featured Image (version 2.0 released in March 2026) also lets you attach, change or remove the image without opening the post.
Automatically assign an image to posts that have none
If you move from a theme without featured images to a theme that uses them, you can automatically set the first photo of each post as its featured image. Be careful, though: the Autoset Featured Image plugin I tested for this has not been updated for 9 years according to its WordPress.org page. I would no longer install it on a live site without trying it on a copy first.
Another approach is to define a fallback image. The Default Featured Image plugin (over 60,000 active installations, tested up to WordPress 7.0) displays a default image for every post that has none.
Recover images after a migration
If you have migrated your content from Blogger or OverBlog to WordPress, the images often remain hosted on the old platform. A tool such as Cache Images scans your posts and brings the files over from the original site, so whatever you do, do not delete the old blog before the process is finished. Here again, be careful: its WordPress.org page shows a last update 3 years ago and a plugin not tested with the last three major WordPress releases. Back up the site first, and test on a copy if you can.
Once your images are imported (check carefully), you can attach them to your posts manually or with one of the plugins above.
Frequently asked questions about the featured image
What is the difference between a featured image and a post thumbnail?
There is none. Featured image is the name used in the WordPress interface, and Post Thumbnail is the name used in the code. In the French interface, it used to be called image à la une and is now called image mise en avant.
What size should I choose for a featured image?
It depends on your theme, but an image at least 1200 pixels wide in landscape format works in most cases and meets Google Discover’s requirements.
Why is the Featured image area missing?
Either the theme does not declare the feature, the content type does not support it, or the panel has been hidden in the editor preferences.
Why does my image appear twice in the post?
Because the theme already displays it automatically at the top of the post and it was also inserted in the content. Just remove one of them.
Does removing the featured image delete the file?
No. The image is only detached from the post: the file is still available in the Media Library.
Does a featured image need alt text?
Yes, unless it is purely decorative. You fill it in from the Media Library, in the image’s Alternative Text field.
Can I set a default featured image?
WordPress does not offer this natively. Some themes do, and a plugin such as Default Featured Image takes care of it.
In short!
The featured image is easy to use, but it matters more than it seems: it is the first image people will see, on your site and beyond. Get into the habit of uploading an image at least 1200 pixels wide, compressed, with alt text filled in, and check how it looks on the home page, on the post and on mobile.
And if you are choosing a theme, click everywhere on its demo, especially on the featured images to see how they behave: do they have a link? Where does it point? Are the images cropped? Can you adjust their format without touching the code? With a classic theme, a behaviour built in by the author can usually only be changed by editing the theme files. With a block theme, you stay in control.
