For such basic requirements, Irfanview is a possible solution. It should be on everyone's PC simply because it's probably the best image-viewing program that there is. However, as well as simply viewing images, it offers plenty of basic image manipulation tools (with a good help file to explain their use). It's particularly good at dealing with red-eye:
http://www.irfanview.com/
However, if you want the best free alternative to Photoshop (with more advanced facilities than Irfanview), Serif PhotoPlus 6 is the software to go for:
http://www.freeserifsoftware.com/software/Phot oPlus/default.asp
Chris