I'm fully aware of what a zip/rar is and does, no need to explain that any further, but thanks for trying anyhow

My main point was that the files increase in size over their jpg counterparts, that I packed them in a cbz so that Calibre could read them is irrelevant.
Thanks for the tip on the commandline version. Calibre shows all the same functions it seems, but that's nice to know anyway

This topic (1st post) and comic2lrf seem to disagree a bit about the actual screensize. Calibre uses 584x784 appearantly. This will cause the software to either resize on the resolutions mentioned here or the ones produced by calibre right?
Small addition: size is not an issue here, I want an as good as possible image quality 'on the reader', not on the PC. That the lrf was larger than the cbz was more something I noticed and not a real issue.