Image swap

Image swap refers to the rare event when a post's attached image is erroneously replaced by the attached image of an unrelated post. Sometimes only the thumbnail is swapped, other times a "full swap" swaps the true, expanded images entirely. This seems to happen when images are processed at the same time in the eyes of 4chan's servers. 4chan servers index images by a 13-digit UNIX timestamp which has the precision of a millisecond, which makes collisions not too hard given you roll the dice enough times. As of 2021, image swaps are not too infrequent on boards like /pol/, /v/ and /vg/, which average ~100 posts per minute.

Further reading

- Instances of image swaps are often reported at the time's respective meta discussion discussion general (if it is alive): [1]