Probably of no use to many, but meh.

Being the space conservation freak that I am, I've decided to compress all my JPEG images to packJPG to save a few GB on my HDD.
Unfortunately, packJPG is less convenient as there's no application to view .pjg files directly.  This plugin aims to solve that, at least for me, by offering the ability to view .pjg images in XnView.

To install, put Xpjg.usr in XnView's plugins folder.  This also works with the Windows version of XnViewMP, but I doubt it for Linux/OSX as the .usr file is essentially a renamed .dll

Note that this only works with packJPG 2.5/2.5a files (not earlier and probably not later versions).  Also, packJPG decompression is very slow, and XnView doesn't appear to multithread generate thumbnails unfortunately.  There's probably some scope for speed improvements down the track, if I can be bothered.

My crappy source code can also be found below.