Great for bulk resizing of images! - http://picasa.google.com/index.html

A free software download from Google.

Picasa is software that helps you instantly find, edit and share all the pictures on your PC. Every time you open Picasa, it automatically locates all your pictures (even ones you forgot you had) and sorts them into visual albums organised by date with folder names you will recognise. You can drag and drop to arrange your albums and make labels to create new groups. Picasa makes sure your pictures are always organised.

Picasa also makes advanced editing simple by putting one-click fixes and powerful effects at your fingertips. And Picasa makes it a snap to share your pictures – you can email, print photos home, make gift CDs, and even post pictures on your own blog.