Hi Dagwood
One of the best and easiest and also one of the quickest photo graphic viewers i have ever used that resize and will also let you edit and do multiple tasks.
it will let you resize either by pixels or actual size is acdsee downloadable from the net free trail with the option to buy later.
for any one who stores lots of photo's once you double click on the photo to make it full screen it will flick and change the photo's as quick as you turn the wheel on the mouse
http://www.acdsee.com/
Hope this helps