IrfanView

Why are most comments referring to having used this in the past tense? I was under the impression that it was still the best image viewer in town, on Windows at least

Because of a few things:

1. Windows 11 now ships with quite a decent and powerful image viewer/editor that covers most average users' use cases, therefore lowering the demand from people to go out of their way to find alternatives, like in the Windows XP days, which is a good thing (less likely to go download malware from the first Google result of "image viewer for Windows XP").

2. PC usage behavior has changed a lot since then. Many people don't even have PCs at home anymore, and people now have most of their pics in the cloud or on their phone or some external NAS that comes with it's own browser viewer app, instead of hoarding them all on their home PC hard drive, further lowering the need to seek out dedicated image viewers to manage giant offline collections of digital camera pics(I mean I still do, but I'm a minority nowadays).

These two factors combined meant the death of the third party PC image viewer app. Yeah, Irfan might be "the best", but the need for the best in this sector has declined significantly, and most users are now fine with "good enough".

It's not.

It made more sense to go through the effort to install IrfanView when there was no image previewer built into windows, in the days of Windows 95/98/ME/2000. Those only had MS Paint, and I think some versions only supported bmp files (no jpeg or gif). Windows XP had an ok image previewer.

The built-in viewer in windows is fine. I can't really think of a feature that it doesn't have that I need. Could you say why irfanview gets your vote?