Twitter card not showing the image? Five causes, ranked

X no longer runs a public card validator, so diagnosing a broken card means reasoning about the tags yourself. In practice it is nearly always one of five things, and they show up in roughly this order.

1. twitter:card is missing or set to summary

This is the overwhelming favourite. summary produces a small square thumbnail beside the text; summary_large_image produces the full-width photo card everybody actually wants. If the tag is absent, X guesses — and often guesses small.

<meta name="twitter:card" content="summary_large_image" />

2. The image is an SVG

X does not render vector images. If your build pipeline points og:image at a logo SVG the card appears with an empty frame. Export a PNG or JPEG for sharing.

3. The image URL is relative or http

Crawlers do not resolve relative paths against your page, and X refuses to load an insecure image inside a secure timeline. The value must be a complete https address.

4. The file is too big, or too small

Over about 5 MB the fetch is abandoned. Under 600x315 the large card is not available at all, so you fall back to the thumbnail no matter what twitter:card says. 1200x630 at under 300 KB clears both limits comfortably.

5. The image is behind something

Authentication, hotlink protection, an aggressive bot rule at your CDN, or a robots.txt that blocks the crawler. If a plain request for the image URL does not return the file, the card cannot use it.

Check all five at once

The Twitter Card validator on this site reads your tags, fetches the real image to measure format, dimensions and weight, and renders the X card as it will appear — so you can see which of the five you have hit.