There's no single official WordPress spec — but 1200×628 matches what Facebook, LinkedIn and most link previews expect, so it's the safest all-purpose choice.
WordPress itself doesn't enforce a featured image size — your theme decides how it's cropped and displayed. But when someone shares your post link on Facebook, LinkedIn or Slack, those platforms pull your featured image and crop it to their own preview size. 1200×628 is the size that satisfies all of them without an awkward crop.
Open Squeezr and drop in your featured image.
Turn on Resize, unlock the aspect-ratio lock, and set width and height to 1200 × 628.
Choose Crop mode to fill the frame completely — most blog headers and photos aren't natively this ratio.
Export as JPG at 80% quality — featured images are usually viewed small, so higher compression is barely noticeable.
Upload as your Featured Image in the WordPress post editor.
Skip the manual math — open Squeezr with this preset already dialed in.
Open Squeezr preset to 1200×628 →1200×628 is roughly a 1.91:1 ratio, which is what Facebook's Open Graph spec and LinkedIn's link preview both use. Sizing your featured image to this ratio from the start means your post looks intentional wherever it gets shared, instead of getting an off-center auto-crop.
Some WordPress themes crop featured images to their own specific ratio for the blog grid or single-post header. 1200×628 is wide enough to crop down safely for almost any theme's own display size, while still being the right shape for social sharing — it's the safest single size to standardize on if you don't want to export multiple versions per post.