What you are seeing: On X your link shows a small square image to the left of the text rather than a large image above it.
The difference on the timeline
summary_large_image renders your image across the full width of the card with the title and description underneath. summary renders a small square thumbnail beside the text, taking up a fraction of the vertical space.
In a scrolling timeline that difference is substantial. The large card is several times the visual footprint and the image is legible; on the small card the image is decoration at best and often unreadable.
When summary is right
Rarely, but not never. If your image is genuinely incidental — a generic avatar, a directory listing, a profile page where the text is the content — the small card is honest about that and the large layout would just stretch a weak image across the timeline.
For articles, landing pages, products, documentation and essentially anything with a designed social image, summary_large_image is the right choice.
Check the image fits the layout
summary_large_image expects a 1.91:1 image, the same ratio as the Open Graph recommendation. If you are switching from summary, check the image is 1200 × 630 rather than the square asset the small card was fine with — a square image in a large card gets centre-cropped and loses roughly half its height.
Frequently asked
Does changing twitter:card update posts I have already shared?
No. X caches card metadata per URL. Existing posts keep the old layout. Update the tag, then confirm the new card renders before sharing the URL again.
What image size does summary_large_image need?
1200 × 630 at a 1.91:1 ratio, the same as the Open Graph recommendation, with a hard minimum around 300 × 157. One image serves both if you build it at 1200 × 630.
I set summary_large_image but X still shows the small card. Why?
X silently downgrades to summary when the image is under 300 × 157 pixels, even if twitter:card says summary_large_image. There is no error. Use a 1200 × 630 image so the large layout actually renders.
Check your page
Run your URL through the checker to confirm the fix is live and see how the card renders on every platform.
Test a URL