WordPress Featured Image Size: 1200×630 + How to Find Yours

Short answer: if you do not know your theme’s size yet, use 1200 x 630 pixels (about 1.91:1). It is the link preview size Facebook recommends, and SEO plugins usually use the featured image as the share image.

On the post itself, the size that counts is the one your theme displays. WordPress stores every upload in several sizes, and the theme picks which one appears. Classic themes set that with set_post_thumbnail_size() or add_image_size(); block themes set it in the Featured Image block. If the theme crops to 16:9 or square, a 1200 x 630 image can lose part of its left and right edges. Find your theme’s size (four ways below), then upload an image at least that large, or about twice as wide for sharp results on high-density screens.

To see every size WordPress will create from a particular image, drop it into the WordPress image sizes tool.

Which size to use, by where the image appears

Where the image appears	Size to upload	Notes
Your posts, theme size not known yet	1200 x 630, or 2400 x 1260 for sharper results	Also works for link previews while you find your theme’s size
Your posts, theme size known	About twice your theme’s featured image width, at the same aspect ratio	WordPress makes smaller copies of an upload, never larger ones
Facebook link previews	At least 1200 x 630 (about 1.91:1); 1200 x 628 is almost the same shape	From Facebook’s sharing guidance
Google Discover	At least 1200 px wide, 16:9 (for example 1200 x 675)	From Google’s Discover guidelines

WordPress image sizes at a glance

Every image you upload gets resized copies for each registered size. These are the sizes WordPress core registers, with the defaults from the Theme Handbook and the core function reference:

Size name	Default dimensions	Can you change it in Settings > Media?	Notes
thumbnail	150 x 150, cropped	Yes	Has a “crop to exact dimensions” checkbox
medium	300 x 300 max	Yes	Scaled proportionally
medium_large	768 wide, no height limit	No	Used mainly in srcset
large	1024 x 1024 max	Yes	Scaled proportionally
1536x1536	1536 x 1536 max	No	Added in WordPress 5.3 for high-density screens
2048x2048	2048 x 2048 max	No	Added in WordPress 5.3 for high-density screens
post-thumbnail	Set by the theme	No	Only exists if the theme calls set_post_thumbnail_size()
full	Your original upload	No	Very large uploads are scaled down first (see below)

“Max” means WordPress fits the image inside that box and keeps its proportions. A 2000 x 1000 photo becomes 1024 x 512 for large, not 1024 x 1024.

Themes and plugins often add more sizes with add_image_size(). WooCommerce, for example, adds its own product sizes, which our WooCommerce product image size guide covers.

One more rule affects big uploads. Since WordPress 5.3, if an image is wider or taller than 2560 pixels, WordPress scales it down and uses the scaled copy as the largest available size. That threshold comes from the big_image_size_threshold filter, whose default is 2560. If you are seeing -scaled in file names and want to know whether to turn this off, read how to disable scaled images in WordPress.

Where the featured image size actually comes from

A featured image is any image you set in the Featured image panel of the post editor. What visitors see depends on how the theme prints it.

Classic themes

A classic theme turns on featured images and registers the size in its functions.php:

add_theme_support( 'post-thumbnails' );
set_post_thumbnail_size( 1200, 675, true );

set_post_thumbnail_size() registers a size named post-thumbnail. The third argument controls cropping. With false (the default), WordPress scales the image to fit inside 1200 x 675. With true, it cuts the image to exactly 1200 x 675 from the center, so anything outside a 16:9 box is lost. You can also pass an array such as array( 'center', 'top' ) to choose which part is kept.

Many themes register extra named sizes for different templates:

add_image_size( 'hero-wide', 1600, 900, true );
add_image_size( 'card', 600, 400, true );

The template then chooses one by name:

if ( has_post_thumbnail() ) {
	the_post_thumbnail( 'hero-wide' );
}

Called with no name, the_post_thumbnail() uses post-thumbnail. So the real featured image size on a classic theme is the size named in the template, and a blog archive can use a different one from the single post view.

Block themes

Block themes, including the free themes on this site, print the featured image with the Featured Image block. The core blocks reference lists its settings, including sizeSlug (which registered size to load), aspectRatio, width, height and scale.

That changes where you look. Open Appearance > Editor, edit the Single Posts template, and select the Featured Image block. The sidebar shows which image size it loads and whether an aspect ratio is set. The aspect ratio is applied in the browser with CSS, so the file stays the same and the visible frame changes. If the block asks for a 16:9 frame and your image is square, part of it is hidden. Archive and home templates can use different settings from the single post template, so check each one.

To check that last point with real settings instead of a general claim, we opened the actual templates/*.html files inside the four free block themes this site distributes and read the aspectRatio attribute WordPress stores on each theme’s Featured Image block:

Theme	Archive / home template	Single / page template
Civic Brief	Cropped to 16:9	Not cropped (native proportions)
Portfolio Plate	Cropped to 4:3	Not cropped (native proportions)
Ledger Docs	No featured-image block on archives	Not cropped (native proportions)
Quietype	No separate archive block	Cropped to 16:9 on both single and page

Two of the four themes (Civic Brief, Portfolio Plate) crop on the archive/home template but leave the single post uncropped, confirming that “check each template” is not just a theoretical warning. This is a check of four themes, not a universal rule, and the exact size slug each block requests was out of scope for this pass since none of the templates set a sizeSlug attribute.

Does a hard crop actually lose the edges? The real math, tested

The claim that a 16:9 or square crop “cuts off the sides” depends on the exact pixels involved, not just the ratio. WordPress decides this with image_resize_dimensions(), the core function behind every cropped size. It clamps the crop to min(requested, original) in each dimension, then crops the larger of the two ratios — so it can only crop pixels that exist, and it never enlarges the source to hit a crop target. We ported that function’s crop branch line-for-line into Node.js and ran four real cases through it:

Upload	Theme crops to	What WordPress actually does
1200 x 630 (the “short answer” size above)	1200 x 675 (16:9)	No edges lost. The crop would need more height than the upload has, so WordPress’s own math caps the result at 1200 x 630 and skips making that derivative — the original is used as-is.
2400 x 1260 (this guide’s “upload 2x” advice)	1200 x 675 (16:9)	80px lost off each side. WordPress crops a centered 2240 x 1260 slice out of the 2400px width, then scales it down to 1200 x 675.
1200 x 630	630 x 630 (square)	285px lost off each side, cropped to a centered 630 x 630 square before any scaling.
1600 x 900 (already 16:9)	1200 x 675 (16:9)	No edges lost. Matching aspect ratio needs only downscaling.

The practical takeaway: a stock 1200 x 630 upload is often too small to actually get hard-cropped by a 16:9 theme — WordPress just quietly skips that derivative instead. Edge loss shows up once you follow the “upload at 2x” advice above, which is also when it’s worth keeping your subject centered. Full script and output: seo-research/first-hand-test/wordpress-featured-image-size-2026-11-06.txt.

How to find your theme’s featured image size

Try these in order. The first one that gives you an answer is enough.

1. Check the theme documentation. Good themes state the recommended featured image size. If it is listed, use it.

2. List the registered sizes with WP-CLI. If you have command-line access, wp media image-size prints every registered size with its width, height, crop setting and ratio:

   wp media image-size

3. Search the theme files. In a classic theme, look in functions.php (and any files it includes) for set_post_thumbnail_size and add_image_size, then look in single.php or the template parts for the name passed to the_post_thumbnail(). In a block theme, check the Featured Image block in the Site Editor as described above.

4. Inspect a live post. Right-click the featured image, choose Inspect, and read the file name in src. WordPress adds the dimensions to resized copies, so my-photo-1200x675.jpg tells you the theme loaded a 1200 x 675 copy. Also look at srcset, because the browser may pick a smaller copy on narrow screens. No dimensions in the name means the full-size file was used.

Once you know the target, run a sample image through the image sizes tool to check what each derivative will look like before you upload a batch.

Choosing the upload size

With the theme’s size known, four choices decide whether the result looks right.

• Width. Upload at least the width the theme displays. For sharp results on high-density phone and laptop screens, aim for about twice that width. For a 1200px wide slot, that means 2400px. WordPress makes smaller copies from your upload and never makes larger ones, so an undersized original is a common cause of a blurry image after upload.
• Aspect ratio. Match the ratio of the theme’s crop. If it crops to 16:9, give it 16:9 and keep the subject near the center so a hard crop does not cut off heads or text.
• File size. A 2400px photo saved as JPEG at sensible quality is typically well under a megabyte, though the exact number depends on the photo’s detail and your quality setting. Uploading a 6000px camera file only adds work: WordPress scales anything over 2560px down anyway, and the extra pixels never reach visitors. Every size WordPress generates from that upload is stored too, so a library of oversized originals is a common reason a WordPress uploads folder grows too large.
• File format. WordPress has accepted WebP uploads since version 5.8 and AVIF since 6.5, as long as your server’s image library supports them. Both usually give a smaller file than JPEG at similar quality. If your featured images already look soft after upload and the size and ratio are both right, the cause is more often WordPress’s default JPEG compression than the registered size.

The social sharing image is a separate job

When someone shares your post on Facebook, LinkedIn or other networks, the preview comes from the og:image tag, which SEO plugins usually fill from the featured image. Facebook’s sharing documentation recommends images of at least 1200 x 630 pixels, kept as close to a 1.91:1 ratio as possible.

You will also see 1200 x 628 recommended. That one is almost exactly 1.91:1, while 1200 x 630 works out to about 1.90:1. The two are only 2 pixels apart in height, so either works.

If your theme’s display size is also close to 1.91:1, one 1200 x 630 (or 2400 x 1260) upload works for both. If the theme crops to 16:9 or square, keep important content away from the left and right edges, or set a separate social image in your SEO plugin.

Google Discover has its own image advice. Google’s Discover guidelines recommend images at least 1200 px wide, more than 300,000 pixels in total, in a 16:9 ratio such as 1200 x 675. Large images also need the max-image-preview:large robots setting, which WordPress has added by default since version 5.7 unless the site is set to discourage search engines.

How to change the featured image size

Where you make the change depends on the size and on your theme.

Core sizes (thumbnail, medium, large). Go to Settings > Media and change the width and height. The Settings Media screen documentation describes the fields, including the crop checkbox for thumbnails.

Theme sizes in a classic theme. Do not edit the parent theme, because a theme update will overwrite your change. Add the new values in a child theme’s functions.php. Registering a size again with the same name replaces it, and the child theme’s setup should run after the parent’s:

add_action( 'after_setup_theme', function () {
	set_post_thumbnail_size( 1600, 900, true );
	add_image_size( 'hero-wide', 1600, 900, true );
}, 11 );

The priority of 11 makes this run after a parent theme hooked at the default priority of 10. Check the parent’s code and adjust if it uses a later priority.

Block themes. Change the Featured Image block’s image size and aspect ratio in the Site Editor template. No code is needed, and the change applies to every post using that template.

One image, no code. To choose what a crop keeps on a single image, open it from Media > Library and click Edit Image. Crop it to your theme’s ratio (the crop tool takes an aspect ratio such as 16:9) or scale it, then save. WordPress applies the change to all of that image’s sizes and keeps the original file, so Restore original image can undo it later.

Regenerate existing thumbnails

A changed size only applies to new uploads. Images already in your media library keep their old copies until you rebuild them. The wp media regenerate command does this:

wp media regenerate --yes

Useful options from the WP-CLI documentation:

• --image_size=hero-wide rebuilds only that size. Repeat the flag for several sizes.
• --only-missing creates sizes that do not exist yet and leaves existing files alone, which is faster after adding a new size.
• --skip-delete keeps the old thumbnail files. Use it if other sites, newsletters or feeds link directly to those files.

Without command-line access, the Regenerate Thumbnails plugin from the WordPress.org plugin directory does the same from the dashboard. Take a backup first on a large library, because regeneration rewrites a lot of files.

Common mistakes

• Stopping at 1200 x 630. It is a good starting point and suits link previews, but if your theme crops to 16:9 or square, part of the image is cut. Check your theme’s size before you upload a batch.
• Turning off the generated sizes to “keep the original.” If the theme has no smaller copies, it can end up loading the full file on every screen, which slows the page on phones. The resized copies exist to prevent that.
• Editing image size code and skipping regeneration. The code works, but only for new uploads. This is why many people decide a size change “did nothing.”
• Changing the size in the parent theme. The next theme update removes it. Use a child theme or the Site Editor.

If the image still looks wrong after you have matched the size, the ratio, and regenerated, check the file name the browser loaded against the sizes the image sizes tool says WordPress should create. When they differ, an optimization plugin or a CDN image resizer sitting between WordPress and the visitor is a likely cause — it can serve its own resized version instead of WordPress’s.

Sources

• WordPress Developer Resources: Featured images and post thumbnails (Theme Handbook), set_post_thumbnail_size(), big_image_size_threshold
• WP-CLI: wp media image-size, wp media regenerate
• WordPress documentation: Settings Media screen
• WordPress core dev notes: WebP support in 5.8, AVIF support in 6.5, max-image-preview in 5.7
• WordPress source code: image-edit.php, media.php (image_resize_dimensions())
• Meta for Developers: Images in link shares
• Google Search Central: Google Discover