Link preview shows no image? 7 og:image checks for Slack, X, Discord and LinkedIn
Your page looks fine in the browser, but when you paste the URL into Slack, X, Discord or LinkedIn you get a title and maybe a description, with no image. The crawler usually isn't broken. It's almost always one of these.
1. The tags only exist after JavaScript runs
Link-preview crawlers read the raw HTML the server returns. Most don't execute JavaScript. If your og: tags are injected by React/Vue on the client (a plain SPA, or react-helmet without SSR), the crawler never sees them.
Check what the crawler sees:
curl -s https://yoursite.com/page | grep -i 'og:image' If that prints nothing, render the tags on the server (SSR/SSG, or your framework's metadata API).
2. og:image is a relative URL
Use an absolute URL with the scheme:
<meta property="og:image" content="https://yoursite.com/og/page.png"> /og/page.png or //cdn... is a common reason for "title but no image".
3. The image URL doesn't return an image
Open the image URL in a private window, and also run:
curl -sI https://yoursite.com/og/page.png You want 200 and content-type: image/png (or jpeg/webp). Common failures: a redirect to a login page, a 404 from a dynamic OG route, hotlink protection, or an HTML error page served with a 200.
4. A firewall is blocking the crawler
Bot-protection settings (a CDN's "bot fight" mode, WAF rules, rate limits, robots.txt disallowing everything) can block facebookexternalhit, Twitterbot, Slackbot, Discordbot or LinkedInBot. Test with the crawler's user agent:
curl -sI -A "Twitterbot/1.0" https://yoursite.com/page A 403 or a challenge page here explains a missing preview even when everything else is correct.
5. Wrong size or too heavy
1200 × 630 (about 1.91:1) is the safe default that every major platform crops well. For X, set twitter:card to summary_large_image, or you get the small square card. Keep the file small: X rejects images over 5 MB, and smaller files simply load more reliably for every crawler. A tall phone screenshot will be cropped to a strip.
Size and per-platform notes: OG image size guide (includes a test your link preview checklist).
6. The platform cached the old (broken) preview
Platforms cache what they scraped the first time. After you fix the tags:
- Facebook: Sharing Debugger → "Scrape Again".
- LinkedIn: Post Inspector re-fetches the URL.
- X, Slack, Discord, WhatsApp: no public refresh button. Change the image filename or add a query string (
og.png?v=2) so it counts as a new URL.
7. Missing the basic tag set
A minimal block that works everywhere:
<meta property="og:title" content="Page title"> <meta property="og:description" content="One sentence."> <meta property="og:url" content="https://yoursite.com/page"> <meta property="og:image" content="https://yoursite.com/og/page.png"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="630"> <meta name="twitter:card" content="summary_large_image"> og:image:width/height let some crawlers render the card on the first share without downloading the image first.
Making the 1200 × 630 image
If you don't have a designer, ogkit is a free in-browser card maker I built. It exports a 1200 × 630 PNG (or a JPG kept under 300 KB, which WhatsApp previews handle more reliably) and copies the tag block above. Nothing is uploaded and no account is needed. There's an optional paid preset pack ($12) if you want more layouts.
Related (same Ship Kit): App Store screenshot sizes in 2026 · Favicon cache fixes after deploy · LinkedIn OG image size · WhatsApp link preview.
This post was written by an AI agent working for the author and checked against the platforms' docs. ogkit is MIT-licensed: repo.