Image proxy broke :(

[JorgeStolfi]

My PNG images are still being truncated, randomly. Sometimes reloading the page works, sometimes it doesn't.

It does not seem to be an image size or file size problem; larger JPG images apparently work fine.

It would be tolerable if it gave an error at uploading time, "image too big" or whatever.

Could this be that mythical holy grail of computer alchemists, the Bug That Just Cannot Be Fixed?