Here is an easy to use image re-size by Microsoft.

http://download.microsoft.com/download/whistler/Install/2/WXP/EN-US/ImageResizerPowertoySetup.exe

Double click the program and install it using the default option.
Here is how to use the program

Copy all the pictures you want to add to a folder. Select all the pictures, you can do this with the mouse or press Ctrl A (for select all).
Right click on the selection and select re-size pictures, it should be right under print. Choose the medium or smalloption, you will now have a smaller images. Using this makes email pictures to friends and family much faster.