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There is no single featured-image size that works for every WordPress site. Your active theme determines how a featured image is displayed and may crop or scale it for different layouts. Check the theme’s guidance and the largest place the image will appear, then preview the result. If Google Discover is a target, Google separately recommends an image at least 1,200 pixels wide, with more than 300,000 total pixels and a 16:9 aspect ratio; that is a Discover recommendation, not a WordPress requirement.
Why WordPress has no universal featured-image size
A featured image—also called a post thumbnail—is an image representing a post, page or custom post type. WordPress supports featured images, but the active theme determines whether and how it outputs them in its templates. A post header, homepage card, archive listing and hero area may all render the same source image differently. The WordPress Theme Handbook describes the built-in image-size options and explains that themes can register custom sizes.
That distinction matters: the dimensions of the uploaded file, a generated WordPress image size and the size at which a theme displays an image are not necessarily the same. A theme can crop an image to fit a chosen shape, or scale it proportionally. A single recommended number without the theme and display slot can therefore be misleading.
WordPress’s built-in sizes are options, not a universal recommendation
The WordPress Theme Handbook lists these default generated-size settings:
| WordPress size | Default setting | What it means |
|---|---|---|
| Thumbnail | 150 × 150 px maximum | A square maximum size; the result may be cropped to fit. |
| Medium | 300 × 300 px maximum | A size limit, not a promise that every image will be square. |
| Medium Large | 768 px wide; no height limit | A width limit with proportional height. |
| Large | 1024 × 1024 px maximum | A maximum size setting, with proportions preserved unless cropping is applied. |
| Full | Original uploaded resolution | The original dimensions available to WordPress. |
These are WordPress defaults described on the Theme Handbook page dated October 27, 2022. Administrators can change default image-size settings, and themes can register custom sizes, so your site may not use these values. Do not assume that “featured image” means WordPress will always display the 150 × 150 thumbnail or any other one default size.
How to choose dimensions for your theme
Choose a source image that suits the largest intended display and the crop used by the theme. For example, if a wide post header and smaller archive cards both use the featured image, check whether the theme creates separate crops for each. A source that looks good in the header can lose a face, logo or important text in a card crop.
- Check the active theme. Look up its featured-image instructions, settings or template behavior. If you maintain the theme, inspect the relevant templates and registered image sizes.
- Identify the largest display slot. Note where the image appears—such as the article header, a homepage card or an archive—and how large it renders at the widest responsive layout.
- Check the image treatment. Determine whether the theme crops to fixed dimensions, preserves the image’s aspect ratio, or lets you choose an aspect ratio. WordPress’s set_post_thumbnail_size() documentation explains that a registered post-thumbnail size can be scaled proportionally when cropping is disabled, or cropped to the requested dimensions when enabled. The default crop is centered unless crop positions are specified.
- Prepare enough source pixels for that display. Use the display dimensions and crop as your guide. The goal is a clear image at its largest intended size, not an arbitrary maximum resolution.
- Preview every important layout. Check the post itself and card or archive layouts, including narrow screens. Keep essential subjects away from edges that a crop could remove.
Keep pixels, display size and file weight separate
Pixel dimensions describe the image file’s width and height. Display size describes how large the theme renders it on screen. File weight is how much data must load. Increasing pixel dimensions may help an image remain clear at a larger display size, but it also can increase file weight. Compressing an image can reduce file weight, but it does not change the theme’s crop or guarantee that the image remains visually clear.
WordPress’s Image size and quality guidance notes that images wider than a theme’s content area can disrupt layout, and that higher resolution can improve clarity while increasing file size. Choose dimensions for the actual layout, then check the exported image’s visual quality and loading weight.
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If a theme’s registered image dimensions change, WordPress does not automatically resize every previously uploaded image file to the new dimensions. The function reference notes that existing uploads may need thumbnail regeneration after a registered size changes. If an older post still shows an unsuitable crop, check whether the required generated size exists rather than assuming the theme change rewrote the original upload.
Google Discover is a separate image target
If you specifically want images to be eligible for large previews in Google Discover, use Google’s published recommendations as a separate target from your theme’s display needs. Google’s Get on Discover guidance recommends images that are at least 1,200 pixels wide, contain more than 300,000 total pixels and use a 16:9 aspect ratio. Its example is 1280 × 720 pixels, or 921,600 total pixels.
Google also recommends enabling large image previews with max-image-preview:large or using AMP, and specifying a representative image with structured data or the og:image meta tag. These recommendations do not make 1280 × 720 a required WordPress featured-image canvas. A theme may use other shapes and sizes for its own layouts.
Make the composition resilient to cropping
Google says it may crop images automatically. Compose a landscape image so the main subject remains understandable if some of the edges are trimmed. Avoid putting a face, logo or other essential detail right at an edge. Google’s Image SEO Best Practices also advises against generic logo images and extreme aspect ratios for preferred-image metadata.
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Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallMetadata can help identify a relevant representative image, but it cannot guarantee which image preview Google displays. Google describes image-preview selection as automated and says it uses a number of different sources to choose the image shown. Use an image that genuinely represents the page and provide appropriate metadata, but do not promise a particular preview or crop.
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Responsive images, sharpness and loading
A single large source file is not always the best answer for every screen. Responsive image markup can let a browser choose a suitable version for the device and display conditions. Google’s image guidance discusses using srcset and <picture>, with an img fallback. WordPress and the theme may already produce responsive image output; inspect the rendered page before adding a separate implementation.
- Check the actual output. Confirm that the theme’s responsive versions and crop look right at desktop and narrow-screen widths.
- Balance clarity and transfer size. Export and compress to preserve the image’s purpose without sending unnecessarily heavy files.
- Do not upscale indiscriminately. More pixels do not repair a poor crop or guarantee a sharper-looking source, and they can increase file weight.
- Recheck after theme changes. A new template, image-size setting or layout can alter the crop or rendered width.
Check a rendered layout with a screenshot
After choosing and uploading an image, inspect the rendered post or archive card in a browser. Check the crop, sharpness and layout at the sizes that matter to your visitors. A screenshot can document what the page actually shows, but it does not replace checking the theme’s settings or the source image.
Or skip the browser setup
You can capture a page with ScreenshotNeo’s screenshot API using one GET request. Replace the example URL with the published post URL and use your API key:
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curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://stripe.com -o shot.webpSee the ScreenshotNeo API documentation for request options. ScreenshotNeo can remove cookie banners, newsletter popups and chat widgets before capture; bot checks, blank pages and failed loads are never billed. Its MCP server lets AI agents take screenshots. The free plan includes 1,000 screenshots a month with no card, and paid plans start at $5 for 3,000 shots. These captures can help you inspect a page’s rendered appearance; they do not determine the correct dimensions for your theme. Learn about ScreenshotNeo, or sign up free.
Common problems and what to check
- The image looks blurry in the header. Check the largest rendered width and whether the source has enough pixels for that display. Also check whether an overly compressed export is reducing visible quality.
- A face or logo is cut off in a card. Inspect the card’s crop separately from the post header. Reposition the subject in the source image or adjust the theme’s crop settings if available.
- Changing the theme setting did not change an old image. The new registered size may not exist for previous uploads. Check the theme’s generated-size behavior and whether those files need thumbnail regeneration.
- The image overflows or disrupts the layout. Check whether its dimensions exceed the theme’s content area and whether the template constrains image width.
- A Google preview does not use the image you expected. Confirm that the image is representative and that the relevant metadata is present, but remember that Google selects previews automatically and does not guarantee a particular image or crop.
- The page loads slowly after uploading a large image. Review its file weight and responsive output. Optimize the image while checking that compression has not made it visibly poor.
FAQ
Is 1200 × 675 the required WordPress featured-image size?
No. It is a 16:9 dimension that meets Google Discover’s minimum width recommendation and has more than 300,000 total pixels, but WordPress themes can use other dimensions and crops.
Does WordPress always crop featured images to a square?
No. Cropping depends on the registered size and theme behavior. WordPress’s default thumbnail setting is square, but that does not mean every theme uses it for every featured-image placement.
Can I guarantee Google will show my featured image?
No. Relevant images and metadata can inform Google’s automated selection, but they cannot guarantee the preview image or crop.
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