User blog comment:DaNASCAT/Technical Update: September 20, 2011/@comment-1331296-20110920194849/@comment-1331296-20110921020129

It happens randomly. Sometimes it will stick around for an entire month, so we know it's here. Other times it happens to a few images once a day. Reuploading normally doesn't fix it, just causes some major drama with users who don't understand why their image isn't updating.

I shall try that for good luck next time. (: