The og:image tag controls the preview image that appears when your page is shared on social platforms. Using the wrong size means your image gets cropped, distorted, or not shown at all.
Facebook recommends 1200 × 630 pixels. The minimum is 200 × 200 — smaller images may not display. Facebook crops the image to fit its preview container, so keep important elements away from the edges.
LinkedIn uses 1200 × 627 pixels for shared links. Like Facebook, it pulls from og:image. Use a horizontal landscape image — LinkedIn does not display square or portrait images well in link previews.
Twitter (X) with summary_large_image expects a 2:1 aspect ratio. The ideal size is 1200 × 628. With summary card, Twitter shows a 1:1 square crop. Images must be at least 144 × 144 for summary cards.
Slack respects og:image and displays it as a thumbnail beside the page title and description. It will show images as small as 80 × 80 but larger images look better.
WhatsApp pulls og:image for link previews. It displays the image in a square crop, so an 1:1 version of your key visual works best, though it will use the og:image at whatever ratio it is.
The safest universal approach: create a 1200 × 630 image that looks good at any crop, keep the key content in the center, and keep file size under 1MB. Use JPEG for photos and PNG for graphics with text.