The Right Size for a Social Share Image

Use 1200 × 630

That is a 1.91:1 ratio, which is what Facebook, LinkedIn, Slack and Discord all expect, and what X uses for a large summary card. Every other platform either matches it or crops predictably from it.

Going larger gains nothing — platforms downscale. Going smaller is where it breaks: under 600px wide, most switch from the large card to a small thumbnail beside the text, which is a much weaker link.

Design for the crop

Different surfaces crop differently. A square crop for some mobile layouts, a tighter horizontal one in others. Keep anything that must be readable — a logo, a headline — within the middle 80% and nothing important in the outer margin.

Text in a share image should be large. It is often displayed at 300px wide or less in a chat window; body-sized text becomes an unreadable smudge. If it matters, set it at a size that survives being a third of its original.

Format and file size

PNG or JPEG. WebP and AVIF are excellent formats that several preview bots still refuse to fetch, and a refused image produces no card at all.

Stay under about 5MB — some platforms cap lower. And the URL must be absolute and publicly reachable: no login, no hotlink protection, no redirect chain. Preview bots are anonymous, patient with nothing, and give no error when they give up.