Shared links now show a picture

Paste a link to a course or a product page into a chat, a post or an email, and you got a bare underlined URL. No picture, no card — the sad grey rectangle, or nothing at all. Meanwhile several of those pages had a hand-made preview image sitting right there in their own folder, going unused.

Two things were wrong, and the second one is the interesting one.

The pages that did have a preview image were storing it under one name while the part of the platform that writes the preview tag was looking for a different one. The two never met, so the tag was simply never written — which is why not a single product or course page has ever had a preview picture, no matter how much care went into making one. They are all connected up now.

The bigger problem was that having a picture at all was optional. A page only got a preview if somebody had remembered to make one, and most pages had nobody to remember. So a preview is no longer something a page opts into: when a page has no picture of its own, the platform now draws one for it — the page's name, its short description and its category, set on a dark card with a colour of its own. Every public page has one, immediately, with nothing to do. If you later add your own image, yours wins.

The colour is picked from the page's own identity, so the same page always shares in the same colour and a row of links from different pages reads as a set rather than a smear. Cards are drawn on demand and cached, so this costs nothing until somebody actually shares something.

Only pages that are already public get a card. Anything that needs a sign-in is untouched — a page nobody may read anonymously does not get a preview, and its name cannot be pulled out of the preview address either.