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WhatsApp link previews: how they work and why og:image dimensions matter more here

OG image file size is the number one issue with WhatsApp previews. Keep it under 300 KB, use JPEG, and test by messaging yourself. Once WhatsApp caches a bad preview, it's hard to fix without changing the URL.

WhatsApp generates link previews for URLs shared in chats using og:title, og:description, and og:image. The preview appears after a short delay while WhatsApp's servers fetch and cache the page. The critical difference from other platforms: WhatsApp has a strict 300 KB image size limit. If og:image is larger than 300 KB, WhatsApp shows no image at all.

By TechCompare · Updated

Platform or focus
Platforms
Social media and messaging apps
Topic detail
WhatsApp previews
whatsapp
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How this is calculated

A 1200x630 PNG can easily exceed 300 KB, especially with photographic content. The fix is to use JPEG for the OG image at 80-85% quality, which typically keeps a 1200x630 image under 200 KB while looking identical for social preview purposes. WhatsApp also requires the image to be at least 200x200 pixels. If the page has multiple og:image tags, WhatsApp uses the last one. The preview is cached on WhatsApp's servers, and unlike Facebook or LinkedIn, there's no public debugger to force a refresh. To test changes, send the URL with a cache-busting query parameter in a chat to yourself.

Verdict

WhatsApp's real constraint is bytes, not pixels. A 1200x630 PNG with photographic content easily clears 300 KB, and anything over that cutoff shows no image at all. JPEG at 80-85% quality keeps the same dimensions under 200 KB with no visible loss. WhatsApp uses the last og:image when multiples are present, and there's no public debugger, so cache-busting query parameters in a self-chat are the only test loop.

More OG scenarios

OG image dimensions
The de facto standard Open Graph image size is 1200x630 pixels, a 1.91:1 aspect ratio.
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Twitter Card types
Twitter Cards control how your URL appears when shared on X (formerly Twitter).
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Facebook vs Twitter tags
Open Graph (og:) tags are the standard, originated by Facebook and now supported by LinkedIn, Discord, Slack, WhatsApp, and most other platforms.
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Related guides

iMessage link previews
WhatsApp and iMessage both rely on og: tags for previews.
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OG image dimensions
Spot where WhatsApp thumbnail sizes come from.
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Frequently asked questions

Why is my WhatsApp link preview missing its image?
File size, almost always. WhatsApp refuses any og:image over 300 KB, and a photographic 1200x630 PNG blows past that easily. Re-encode the image as JPEG at 80-85% quality, which lands around 150-200 KB for the same dimensions with no visible quality loss in a chat bubble.
Does WhatsApp use the first or last og:image tag?
The last one. If your page emits multiple og:image tags (some SEO plugins do this), WhatsApp picks the final tag in document order, while other platforms typically take the first. If your preview keeps showing the wrong image, view the page source and check which og:image appears last.
How do I test WhatsApp link previews?
By messaging the URL to yourself in a chat. There's no public debugger, so the test loop is manual: paste, wait for the card, screenshot, adjust, and append a cache-busting query parameter like ?v=2 to force a refresh. WhatsApp's server-side cache is sticky, so testing the same URL twice shows the old preview.

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