Hi Jim - unfortunately I have only DX7590 images but if you care to google----
I'm sure you'll find plenty to illustrate that that the DX6490, used within its limitations, produces images that not only hold up well nine years after its introduction, but that in (shall we say) viewability, actually surpass some modern cameras. For me, anyway.
If you care to compare the DX6490 against the DX7590 on Imaging Resource's Comparometer, you will, I think, find that there's a slight but noticeable tonal difference AND that the extra megapixel on the DX7590 does not appear to provide any extra detail. In fact, the DX6490 looks slightly sharper!
I think the Z990 - as far as image qualty is concerned - upholds the Kodak tradition and If I could have purchased one for the £ equivalent of the $99 they were obtainable for in the USA, I would have bought one even though I don't need another camera.
I'd best remove the swan pic now as it's not mine and if you have a squint at the Fuji forum you'll find it now has a moderator who's making noises about posted pics that should be in the gallery.
Best of the season to you and yours, Jim.