I'm Matthias Stirner, the developer of packJPG. I'm going to open-source packJPG within the next few weeks, and I figured it couldn't hurt to post the release candidate here for those who want to try it. The final version will be released along the source code.
I already fixed a few bugs, but maybe there are still some other files that can lead to a crash (with the old v2.4, too). If so, please post here or contact me.
Before I open-source, I still need to do some code cleanup, renew the docs, and, most importantly, to settle for a license. I'd go for the GPL, but then I also want to give freeware closed source developers a no-hassles chance to use the library. If someone makes money from my work, however, I want a share of it or at least be asked for permission.
My ideas so far involve dual licensing (GPL+???) or GPL + special permissions for closed source developers. Any ideas via PN or email would be very welcome.