Link-preview cards show the icon, not a cropped poster

A preview card puts its picture in a small square, about the size of a fingernail. The picture it was given, though, was the page's poster — the wide banner graphic made for sharing a link on social media, roughly twice as wide as it is tall.

Squeezing a wide banner into a small square means cropping away most of it. What survived was an arbitrary slice out of the middle: a corner of a chart, half a word, a patch of background. Every card in a grid looked vaguely similar and none of them told you anything.

Cards now show the page's icon instead — the small square mark a site or a node already carries, drawn to be legible at exactly this size. A grid of cards becomes scannable: you recognise each destination at a glance instead of squinting at banner fragments.

This applies to both kinds of card:

• Pages on other portals — the platform reads the icon the page declares, picking the sharpest one on offer (a scalable icon beats a large one, a large one beats a small one). If a page declares no icon at all, its poster is still used rather than showing nothing.
• Nodes on your own portal — the card shows the node's own icon, the same mark you see beside it everywhere else, so a card and a search result finally agree with each other.

Node cards elsewhere in the portal — search results, pinned items — got the same treatment for the same reason. Full-size thumbnail tiles are unchanged: they are poster-shaped, so they keep the poster.