Craig,
I use Irfanview version 3.92 because it seems to be the last version
where the image view (not the thumbnail view, although it does too)
opens maximized by default if you set it there. The current version is
3.98 and although I tried newer versions than 3.92, I kept having to
maximize the viewing window and decided that none of the improvements in
newer versions were compelling enough to lead me to update.
You might feel differently if you had a Lumix camera that records in
RAW format. I upgraded from 3.97 to 3.98 to be able to display my
Panasonic Raw files.
I've used XnView and as others have pointed out, found it to be a
more or less duplicate of Irfanview. Since I only need one such program
and had been using Irfanview longer, XnView got removed.
For me, there's a most compelling reason for using Irfanview over
Xnview. Irfan tries very hard to help with reported problems. I had
distortions in displaying a tiff file produced by Photoshop, and we
spent a couple of weeks sending very large image files across the pond
and discussing them (the distortion occurred in Kodak image viewer
too, but not under Linux, so I guess it was Win98 related). We never
figured out the cause, but he sure gave it a good try.
Pierre-e Gougelet, the author of XNview, by contrast, responded to a
rather critical problem I have with his gflAx.dll rather cavalierly:
I have no answer for this problem, and have no 98SE to check...
This dll was incorporated into the last upgrade to a database program
I use, but refuses to self-register in Windows98SE, at least in four
out of five of my machines (including one attempt with a freshly
installed system). The application won't run at all without the dll,
and the error messages given are cryptic to meaningless (Windows can't
find a required and unnamed library file). I've wasted many hours
trying to find ways to install this dll, and can't muster much respect
for a programmer who cares so little whether his code runs as
advertised or not.