You'd probably do zTxt chunks right? But regardless I'd guess that there's nothing that would cause a renderer to actually read that chunk.
However, it may work with the article's process - a 100x100 png with lots of 2GB-of-nothing iTXt chunks could be gzipped and served with `Content-Encoding: gzip` - so it would pass the "is a valid png" and "not pixel-huge image" checks but still require decompression in order to view it.
Chrome and Safari both crash after using up all OS memory on the task (Safari crashes earlier and not as badly because it has a per-page memory limit)