Why your links share as a bare URL, and how to fix the preview image

What the error means

A page without a valid og:image (or with one that fails to load, is too small or is an unaccepted format) shares to social platforms and chat apps as a bare URL or a broken thumbnail. Twitter needs the twitter:card family or falls back to Open Graph; Slack, WhatsApp, LinkedIn and Facebook read og:image only.

Why Google rejects it

Every platform unfurls a link by fetching its own copy of the page and the image — never the browser cache, and often a different user agent that your CDN may block. That is why a preview can look fine for you and broken for everyone else: their fetcher is a bot, and bot rules apply to it.

How to fix it

1. Add og:image to the page head pointing at an absolute https URL — relative paths and http images are ignored by several platforms.
2. Use 1200×630 PNG or JPG, under about 5 MB. SVG is not rendered by any major platform; an SVG og:image is the same as none.
3. Keep the image publicly reachable: no login walls, no hotlink protection, no expiring signed URLs.
4. Fix caching after a change: platforms cache aggressively. Use their debugger (Facebook Sharing Debugger, PostInspector for LinkedIn) to force a refetch.
5. Add twitter:card (summary_large_image) so X renders the large card instead of falling back.

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