That's what I am doing now, keeping them chronological (for the most part). I don't think it's too confusing, but I hope to get enough art work up that it becomes that way.
I have different sections, sometimes on the same page, it would be nice to somehow differentiate them.
As for how long is new...well, as the site maintainer, it would be whatever you want.
With as busy as our sites are now, it might be a month or two. (I mean the amount of traffic we get, btw.)
Something that I used to do, which you do much of the time, Uatu, is name each new graphic in the news section (I still do this part) and I would provide a direct link to the art (which I don't do anymore - it is a lot of work), so the first time they can get it from the news section, or they can come back later and look through the various pages, or scroll through old news.
P.S.- Hi, LurchBrick! Nice to see you around again.