Mick, download Irfanview. It's small, has a lot of resize options, reads CR2 and other RAW formats. Very limited processing, but it does an excellent job on the things it does do. I have set it as the default viewer for CR2 and other formats so I can just click a pic for a quick look. Takes just seconds to open., and I use it a lot for a quick crop, resize, convert, or to greyscale something. And it takes plugins.
http://www.irfanview.com/main_download_engl.htm
Trev