There is no such thing as “the WordPress featured image size.” WordPress does not register a size called featured, and it never has. Your theme decides which registered size the featured image renders at, which is why the same image looks right on one theme and cropped badly on another.
If you just want a number that works almost everywhere: upload at 1200 x 675 (16:9) and let WordPress generate the rest. If you want the number that is actually correct for your site, this page shows you how to find it in about thirty seconds.
- WordPress has no built-in “featured image” size. The featured image is displayed at whatever registered size your theme asks for.
- Core registers six sizes by default: thumbnail 150×150, medium 300×300, medium_large 768 wide, large 1024×1024, plus 1536×1536 and 2048×2048 for high-density screens.
- Upload larger than you need. WordPress scales down, never up, so a too-small original cannot be fixed without re-uploading.
- Anything with a longest edge over 2560px gets scaled to 2560px on upload, which is a separate behaviour worth knowing about.
- 1200 x 630 is a social sharing recommendation, not a WordPress one. It is a fine upload size, just not for the reason it usually gets given.
The sizes WordPress actually registers
Every image you upload is cut into several copies. These are the defaults in a current WordPress install, and none of them is named “featured”:
| Size name | Dimensions | Cropped? |
|---|---|---|
thumbnail | 150 x 150 | Yes, hard cropped to a square |
medium | 300 x 300 max | No, scaled to fit |
medium_large | 768 wide | No, height is automatic |
large | 1024 x 1024 max | No, scaled to fit |
1536x1536 | 1536 x 1536 max | No, for 2x screens |
2048x2048 | 2048 x 2048 max | No, for 2x screens |
Two things surprise people here. The medium and large values are maximums, not fixed dimensions: an image is scaled until neither side exceeds the limit, so a wide image hits the width first and a tall one hits the height first. And only thumbnail is hard cropped by default, which is why thumbnails cut off heads while other sizes do not.
The 1536x1536 and 2048x2048 sizes are not visible in Settings → Media. They exist so WordPress can serve a sharper file to high-density displays through srcset.
Your theme and plugins almost certainly add more. Page builders, sliders, WooCommerce and form plugins all register their own, which is why an uploads folder grows faster than expected.
How to find your theme’s actual featured image size
This is the part most guides skip, and it is the only way to get a real answer rather than a guess.
The quick way: inspect a live featured image
Open a post on your site, right-click the featured image and choose Inspect. Look at the src attribute. WordPress appends the dimensions to generated files, so you will see something like:
<img src="/wp-content/uploads/2026/08/photo-1024x576.jpg"
srcset="/wp-content/uploads/2026/08/photo-300x169.jpg 300w,
/wp-content/uploads/2026/08/photo-1024x576.jpg 1024w,
/wp-content/uploads/2026/08/photo-1536x864.jpg 1536w">That tells you the theme is rendering the large size. A filename with no dimensions on the end means the full-size file is being used.
The complete way: list every registered size
To see every size your install actually generates, including the ones your theme and plugins added, run this with WP-CLI:
wp media image-sizeNo shell access? Drop this into a snippet plugin temporarily and load any page while logged in as an administrator:
add_action( 'wp_footer', function () {
if ( ! current_user_can( 'manage_options' ) ) {
return;
}
echo '<pre style="background:#fff;padding:20px">';
print_r( wp_get_registered_image_subsizes() );
echo '</pre>';
} );Remove it once you have the list. The current_user_can() check means visitors never see the output, but there is no reason to leave debugging code on a live site. Our guide to adding code snippets safely covers where to put things like this.
So what size should you upload?
Work from the largest place the image will ever be displayed, then add headroom for high-density screens.
- Standard blog post header: 1200 x 675 at 16:9 is a safe, common choice and matches how most themes display a full-width featured image.
- Full-width hero images: 1920 x 1080, since the image spans the whole viewport on a desktop monitor.
- Grid or card layouts: match the theme’s registered size and accept the crop. Square-ish source images survive square crops better than wide ones.
- Never smaller than the display size. WordPress scales down but never up. An 800px image in a 1200px slot will look soft and nothing can fix it except re-uploading.
Aspect ratio matters more than exact pixels. If your theme crops to 16:9 and you upload a portrait photo, the crop takes the middle and the subject’s head disappears. Match the ratio your theme uses and the exact dimensions become far more forgiving.
Where 1200 x 630 actually comes from
You will see 1200 x 630 recommended constantly as “the featured image size”. It is a reasonable size to upload, but the reason usually given is wrong. That number is the Open Graph recommendation, which controls the preview card when someone shares your link on Facebook, LinkedIn or Slack. It has nothing to do with how WordPress displays the image on your own site.
It matters because most SEO plugins fall back to the featured image for the social preview, so one image ends up doing both jobs. If sharing previews matter to you, 1200 x 630 keeps that side happy. Just know you are optimising for Facebook, not for your theme.
The 2560px rule that catches people out
Since WordPress 5.3, any image with a longest edge over 2560 pixels is automatically scaled down to 2560px on upload, and that scaled copy becomes the one used everywhere. You will notice it because the filename gains a -scaled suffix.
For featured images this is almost always fine, and it stops enormous camera files being served to visitors. It only becomes a problem if you genuinely need the full-resolution file on the page. Our guide to disabling or changing large image scaling covers how to raise the threshold or turn it off, and where WordPress keeps your untouched original.
Changing the size, and fixing images you already uploaded
Thumbnail, medium and large are editable under Settings → Media. Sizes registered by your theme are not, and changing core sizes will not change what your theme requests anyway.
To add a size of your own, register it and tell the theme to use it:
add_action( 'after_setup_theme', function () {
// name, width, height, crop
add_image_size( 'post-hero', 1200, 675, true );
} );Put that in a child theme rather than the parent, or an update will wipe it. Our child theme generator will build one for you if you do not have one yet.
The important part: registering a size does nothing to images you already uploaded. WordPress only generates sizes at upload time. After adding or changing a size, regenerate:
wp media regenerate --yesWithout shell access, the Regenerate Thumbnails plugin does the same job from the dashboard. On a large media library either approach takes a while, so start it when the site is quiet.
Frequently Asked Questions
Why is my featured image blurry?
Almost always because the original was smaller than the space it is displayed in. WordPress scales images down but never up, so a 600px image stretched into a 1200px header will look soft no matter what settings you change. Re-upload a larger original. The other possibility is a high-density screen: a 1200px image looks sharp on a standard monitor and slightly soft on a retina display, which is exactly why core generates the 1536 and 2048 sizes.
Why is my featured image cropped strangely?
Your theme is using a hard-cropped size with a different aspect ratio to your image. A hard crop takes a fixed centre section rather than scaling the whole picture, so a portrait photo forced into a wide slot loses the top and bottom. Either upload at the ratio the theme expects, or register your own size with crop set to false so the full image is scaled to fit instead.
Does the featured image size affect page speed?
Yes, and it is usually the single heaviest thing on a blog post. The featured image is often the largest visible element, which makes it the Largest Contentful Paint element that Core Web Vitals measures. Uploading a 4000px file when the slot is 1200px wide means visitors download far more than they need. Upload at a sensible size, let WordPress generate the smaller copies, and make sure your theme is not requesting the full-size file when a smaller one would do.
Can I set a different featured image size per post type?
Yes. Register the sizes you need with add_image_size(), then have your templates request the right one by passing the size name to the_post_thumbnail(), for example the_post_thumbnail( 'post-hero' ). Because the size is chosen at render time in the template, a single-post template and an archive template can display the same featured image at completely different sizes.
Should I delete unused image sizes?
It is worth doing if your uploads folder is out of control, since every registered size multiplies each upload. Unregister sizes you genuinely do not use with remove_image_size(), or filter intermediate_image_sizes_advanced to stop them generating. Two cautions: this only affects future uploads, so old files stay until you clean them up, and removing a size a theme or plugin still asks for means it falls back to the full-size image, which is worse for performance than the size you just deleted.
Related: stop WordPress scaling your images, get the featured image in code, and theme screenshot sizes. Browse all our free WordPress tools, none of which ask for an email address.
