I'm using this baby for years for fast stuff (paintshop pro for the rest) and it is just great. Besides the ability of using photoshop plugins irfanview also creates great html image galeries, multiple image aopperations throug thumbnails an almost everything else besides serious editing.
This is all you need. I dare you to prove me wrong :-)

The finest light weight, speedy, simple, unencumbered, non-dependant and versitile graphics programme I have used. Had it for years and at a minimum it works great as a graphics clipboard.

The only limitation I have found is that it can't deal with large files copied and pasted from photoshop.

I find that running it from a flash drive messes up whatever settings (eg associations and shell menu settings) were set by the Irfanview on the host's hard drive. It's overwriting settings kept by the registry! This is not safe "portable app" behavior, especially if I'm doing this on someone else's machine.

IrfanView is not stealth or even just portable when you activate file associations or shell functions. For this the exe has to be alway on the same place. On a fresh machine or if you move the app folder you need to reregister your desired file associations and of course they are written to the registry. ALL other settings are portable via ini.

Get the portable version here:
http://usb.smithtech.us/apps/irfanview.php

Is there ANY way to work around the file-associations thing? If an USB user re-sets the file associations to his "F: drive" installation this causes problems for the original owner of the PC. I realize it is a Windows thing but I hope someone has a clue to maybe solve this/workaround.

The normal version if portable enough, the new machine doesn't know to call the program if someone clicks on a picture - because guess what - it hasn't been associated with that program. But that's not the programs fault, there is no reason to use a separate launcher.

Faststone is MUCH better!!!

I've tried a lot of alternatives for years. None is as fast as IrfanView, especially in large folders with lots of files. It's the best and the only other picture viewer I use is XnView for its easier way to handle dual screens.

I was unable to find a mirror that would let me select a ZIP file. What was I doing wrong?

John Germann:

http://irfanview.tuwien.ac.at/iview423.zip

What I like is that it can make Windows Icons out of any image - so can Gimp by the way.
- Peace!!! masses

For the File Associations, Shell extensions (Right-click) and other Registry issues, especially in a multi-user environment, have a look at ASSOX http://sites.google.com/site/assoxhome/
Off-topic (not portable)
IrfanView's find for quick-and-dirty icons, but for making proper Windows ICO files (14 different size/resolution in one file - see http://www.axialis.com/tutorials/tutorial-iw015.html, better to use Photoshop and the Icon Plugin from here http://www.telegraphics.com.au/svn/icoformat/trunk/dist/README.html.

Best way I find to make IrfanView portable-friendly is to run a PC-installed version (with Plugins), go to Properties/Settings, under Extensions 'Clear all', then uncheck any 'Shell options'. Then copy the whole IrfanView folder to your USB drive. After doing that, re-enable the extensions and shell options on the install PC. I just drag-and-drop images into an open instance since there won't be file associations on the host machine.

Loving the lossless jpg crop and rotation capabilities. Remarkably simple and effective. Fantastic for already faded photos you don't want to lose any quality / file size on.

switched to xnview long time ago .. but my respect for irfanview never ceased

This is a great piece of software: simple to use and performs almost any task. I especially like the custom/fine rotation feature which allows you to rotate images to a fraction of a degree both right and left. The batch rename and convert feature is fantastic too. It allows you to save in any format. Like many others, I've been using it for years and highly recommend it. The plugins allow you to do almost any task with it and I'm still discovering new things I can do with every day. The help files are easy to follow and it has a nice, clean, uncluttered interface. Incredibly well designed. Great program! (Did I mention it is free?)

website still points to 4.28, but updated portable .zip version 4.30 is available:

http://irfanview.tuwien.ac.at/iview430.zip
http://irfanview.tuwien.ac.at/plugins/irfanview_plugins_430.zip

Here's a mirror for v4.32 Zip file.. the official link is dreadfully slow for some reason:

http://www.mediafire.com/?6jaemprahevz9pu

FiLE: iview432.zip
CRC-32: f79688f7
MD4: c62211a701c3f93db56235a6b9296f12
MD5: 933863d485179823cef096f8dd79d7e0
SHA-1: bd629c83b62c704435fffc72cf5ebcaf1c4e7d8b
SiZE: 1.25 MB (1,312,440 bytes)

I dislike this program,have tried many a version and just dont like multiple windows I guess-I love Xnview Portable to death!

Last version is 4.36 (June 27)

updated to 4.37

Secunia PSI is flagging 4.36 as having security issues. The page and the link should probably be updated to 4.37.

@ billon
@ AndTheWolf
Thanks ... and updated.

IrfanView version 4.38 is out.

@ smaragdus: Thanks ... and updated ;)

V. 4.40 released (2015-07-31)
now have also 64-bit version

@ billon: Thanks ... and updated ;)

Irfanview is one of the oldest, but still one of the best programs of its type. Does just about everything, its fast and very lightweight, and even works from the command-line.

To me It's stealth:
https://www.portablefreeware.com/forums/viewtopic.php?p=86866#p86866