@Pookie:
Giving you some hints to understand how this forum (and others) are built. Actually, when you reply to a topic, be it with 'quick reply' or 'post reply' ('post reply' does the same as 'quick reply' it just gives you more options, you know, bold text, colors, smileys these stuffs), your answer is visible for everyone, everyone sees it and everyone is able to answer it, if you want to talk to a specific person (while in a topic), just put this @xyz thing I'm putting on top of my post or you may use the quote button to structure your answers and adress the ideas one by one. That's also the reason why most forums don't allow off-topic in general sections and don't allow double-posting, because it makes the topics difficult to read.
Private Messages (PM) are mostly used when you want some discussion only with one specific fellow on a not so public interest topic, or hiding secrets
Now for XNview, I believe you need the first package of the list, it's the full app', bigger than you need, but I'm afraid you'll be lost if you download other specific packages.
Note: No one here was born with these forum rules, so don't bother, just take note (: