Also -
Don't overlook Microsoft Photo Editor, which is part of Microsoft Office. It's one of those options you can select or not select during the installation of Office. If you didn't select it when you first installed Office, you can run Setup again to add it. You need your installation CD and the CD key (serial number) for that. It's a very decent little editor, capable of resizing, and of reading statistics on photos (like resolution and print size. The crop tool is pretty bad, however.
I don't know about IrfanView's earlier iterations, but I have Version 4.25 installed on this computer, and it's a pretty full-featured editor, capable of resizing and a whole lot more. It's free for the downloading, and there are plugins to extend its functionality even more.
I also have GIMP, which is basically Photoshop with an interface designed by aliens. It's free, and quite a few people like it, but its learning curve is fairly steep. Which is also true of Photoshop, truth to tell. But GIMP is just downright strange, and not for people who just want to do a few adjustments every once in a while. I have it primarily because in my job, people send me stuff that I have to have Photoshop-like capabilities to read and work with.