Making a link preview (OG) image
The image that appears when a link is pasted into a chat or a post. One 1200x630 covers every service, but each crops it differently, so it needs a safe area.
Updated 2026-09-10
Paste a link into a messenger or a social post and a card appears with a title, a description, and an image. The convention that builds that card is Open Graph, and the image is the OG image. The page's HTML names the image's address in a tag called og:image, and any service that reads the link fetches it for the card.
Without one, the service either grabs a random image from the page or builds a bare card with no image at all. The difference in click-through is large. Any page that will be shared deserves an OG image.
Size: 1200x630
The recommended size is 1200x630 pixels, a 1.91:1 ratio. Facebook set it and everyone else follows. Facebook's minimum is 600x315, but that turns soft on dense screens. Build it at 1200x630 and every service scales down, never up.
| Service | Card ratio | What happens to 1200x630 |
|---|---|---|
| 1.91:1 | Used as is | |
| 1.91:1 | Used as is | |
| X (large card) | 2:1 | 15 pixels trimmed top and bottom |
| Slack and Discord | Varies | Scaled to width, not cropped |
| KakaoTalk | Varies | Scaled to card width; some views crop closer to square |
| iMessage | Varies | Cropped to a square in the small card |
Safe area: the middle 630x630
As the table shows, some services crop close to a square. So anything that must be seen — logo, title, face — belongs inside the central 630x630. Use the 285 pixels on either side only for background and decoration. Built this way, the wide card shows the whole thing and the square card shows the core.
- Text at least 60 pixels tall. The card is seen at 300 to 500 pixels wide, and smaller type does not survive that.
- One line is enough. The card shows the title separately, so the image does not need to repeat it.
- Keep logos at least 60 pixels from the edge. Each service trims a different amount.
- Strong contrast between text and background. The card appears on light screens and dark ones.
- Thin lines and small icons vanish when scaled down.
Weight and format
The service fetches the image the moment it reads the link. A large image takes longer, and some services stop waiting and build a card without one. Keep it under 300KB. A 1200x630 JPG at 85 percent is usually 100 to 200KB; a text-heavy PNG fits under 300KB too. Skip WebP — some services cannot read it.
When the old image keeps showing
Services cache a card once read and do not read it again, which is why an old image can linger for days after a change. Facebook and LinkedIn offer a debugger page that forces a re-read. For KakaoTalk, the reliable fix is to change the image's address itself, for instance by adding a version number to the filename.