WordPress featured image size: dimensions, aspect ratio, and file size

The short answer for a typical blog: upload a landscape image at least 1200 pixels wide in a 16:9 ratio, such as 1200×675 or 1600×900, saved as a compressed JPEG or WebP.

Why WordPress has no single featured image size

Featured images are a theme feature. WordPress's theme handbook says themes "must declare support for the Featured Image function before the Featured Image interface will appear on the Edit screen," and each theme then decides where the image goes: "on your archive page, in your header, or above a post." The theme also registers the sizes it needs, so the same upload can appear as a wide banner in one theme and a square card in another.

What WordPress does itself is make copies. When you upload an image, it generates a version at each registered size. These are the defaults; the thumbnail, medium and large sizes can be changed under Settings, Media:

Size name	Default maximum
thumbnail	150×150
medium	300×300
medium_large	768 wide, no height limit
large	1024×1024
full	The file as uploaded

The theme picks which of these to show in each place, or registers sizes of its own.

There is one more rule. If either side of an upload is larger than 2560 pixels, WordPress scales it down so that 2560 is the maximum width and height, and the scaled copy "will be used as the largest available size." A 6000-pixel photo straight from a camera never reaches your pages at full size.

So the real question is the largest slot the image has to fill, and which crops it will go through.

What the other places need

The featured image travels further than your theme. When a post is shared or shown in Google's feeds, these are the published recommendations:

Where the image ends up	What the platform recommends
Facebook link shares	At least 1200×630 for high-resolution screens, as close to 1.91:1 as possible, file no larger than 8 MB; 600×315 is the minimum for large-image previews
Google Discover	At least 1200 px wide, more than 300,000 total pixels, 16:9, with large previews allowed through max-image-preview:large
Google Search and Images	A relevant, high-resolution image without an extreme aspect ratio, in a supported format
Your theme	Whatever its largest featured slot is; the WordPress default "large" size is 1024 px

Two of these pull in different directions. Facebook asks for 1.91:1 so the full image shows "without any cropping," while Discover asks for 16:9 and says Google "tries to automatically crop the image" to fit. No single image satisfies both exactly, which is why the subject belongs in the middle of the frame.

The size to use

Upload	Ratio	Total pixels	Trade-off
1200×630	1.91:1	756,000	Exact fit for Facebook; Discover crops it to 16:9 itself
1200×675	16:9	810,000	Meets Discover's width and ratio; Facebook trims about 47 px of height
1600×900	16:9	1,440,000	Sharper on large and high-density screens; heavier file
1920×1080	16:9	2,073,600	Full HD; worth it only for full-width hero layouts

For most blogs, 1200×675 or 1600×900 is the answer. Both meet Discover's minimums, crop to a usable 1.91:1 social card, and stay under WordPress's 2560-pixel threshold, so the file you upload is the file WordPress serves as its largest size.

Change the ratio only if your theme demands it: if it shows featured images as square or portrait cards, check its documentation for the size it registers and frame the image so a center crop still works. Avoid text in the image: Google advises against "an image with text" in the og:image tag, and a theme crop can cut text in half anyway.

File size and format

Google's image guidance notes that images "are often the largest contributor to overall page size, which can make pages slow and expensive to load." Compress the file before you upload it rather than relying on the theme to shrink it.

Format follows content: JPEG for photographs, PNG for graphics with text or transparency, WebP for smaller files of either. Google Search supports "BMP, GIF, JPEG, PNG, WebP, SVG, and AVIF," and recommends that the file extension match the file type.

Name the file before you upload it, too. Google says filenames give "very light clues" about an image, and its example is that my-new-black-kitten.jpg "is better than" IMG00023.JPG.

Why a featured image looks wrong

• Heads or edges are cut off. The theme crops to its registered size. Recenter the subject, or upload in the ratio the theme uses.
• It looks blurry. The upload is smaller than the slot, so the browser stretches it. Upload at least as wide as the widest place the image appears.
• Old posts look wrong after a theme change. Sizes are generated at upload, so older images lack the new theme's sizes until a regeneration plugin rebuilds them.
• There is no featured image box in the editor. The theme has not declared support, or the panel is hidden. The handbook notes users "can enable it in their screen options."

Alt text

The featured image needs alt text like any other image. Google calls alt text "the most important attribute when it comes to providing more metadata for an image," and asks for useful descriptions rather than lists of keywords: "Dalmatian puppy playing fetch" beats "puppy." In WordPress you set it in the Alternative Text field of the image in the Media Library, and the theme outputs it with the featured image. Our walkthrough on writing a blog entry includes alt text in its publishing steps.

Choose images while you write the post, not after, and place body images next to the section they explain, as blog post structure covers. Images are one part of blog SEO: they help a page that already answers its query and do little for one that does not.

How Structura handles this

Structura can generate a featured image for every post and, on paid plans, images inside the post body. You choose the aspect ratio once per site from 1:1, 4:3, 3:4, 16:9 and 9:16, so it can match your theme's featured slot; 16:9 is the default and the right choice for most blog themes and social cards. Images are WebP by default, and paid plans can switch to JPEG or PNG for themes that need them.

Every generated image gets alt text describing what it shows and a descriptive filename; there is nothing to switch on. On WordPress, the plugin sideloads the image into your Media Library and sets it as the post's featured image, so WordPress generates its usual sizes and your theme crops it the way it crops any upload. Structura does not pick pixel dimensions for your theme, so if the theme hard-crops to an unusual shape, match the ratio to it. You can replace any image in the WordPress editor; Structura does not touch it again after the post is generated.

On headless sites, images are stored as WebP with the longest side capped at 2048 pixels and metadata stripped, and the Content API returns each featured and body image with its URL, width, height and alt text, plus an Open Graph image field ready for social tags. The features overview shows how images fit into the rest of each post.

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