Why ImageFap picture links expire

A signature and a deadline

Each picture address ends with a signature and a timestamp. Measured against a live gallery, the deadline sat about seven hours and twenty minutes ahead. Ask for the same picture twice within that window and you get the identical signature back, so the deadline is a property of the picture, not of your visit.

A signed picture address split into path, signature and deadline. A validity bar drains over seven hours and twenty minutes, passing the six-hour mark where the cache is refreshed, then turns red and reads links expired. Pressing Resolve refills the bar with a new signature and a new deadline. — The deadline is baked into the address itself. Resolving again mints a new one. Scroll the panel sideways to read it all.

What that means in practice

A gallery resolved now works for the rest of the afternoon. A gallery resolved last night and left in a tab will fail today, and it fails at download time rather than at resolve time, which is why the tool can show you a full grid and still stall on the archive.

The fix is one press

Resolve the same link again. Fresh signatures arrive and the download proceeds. Nothing is cached against your name, so nothing has to be cleared.

Why we cache for six hours and not more

We hold a resolved gallery for six hours, comfortably inside the deadline. It means a popular gallery is read from ImageFap once rather than once per visitor, and it means the addresses we hand out are never close to stale.