It's all filetypes, any file larger than 1mb will not upload and it's affecting all of Jow Forums, 4channel is unaffected
Couple of possibilities: >this is a stopgap measure undertaken by the staff to comply with legal obligations to stop people from posting any of the shooter footage in whole or part (unlikely since it could just spread to 4channel in protest)
>Server-side error (most likely reason)
>Hiro is being a jewish niggerfaggot again and trying to test if he can get away with lowering the max filesize, perhaps to test limiting non-pass users to lower filesizes (also very probable)