If you are using windows xp, try this wonderful tool from microsoft. You can select all the pictures and with on right-click make them any size you want.
This PowerToy enables you to resize one or many image files with a right-click."
At one time I knew how to resize all the images in a folder with one click of the button. My goal was to take normal size .jpg and convert them to good quality email sizable.
Any assistance or reminders appreciated.