Oh Laura, I wish I could help you. I finally learned how to do it, but I can't explain how. It involves Photoshop and alot of complicated instructions. Maybe, if you e-mail your photo to me, I'll be able to re-size it for you.
At least I'll give it my best try!
Try this... Every Windows computer should have an old program called "Paint" You can find it under "Accessories" or go to "run" and type in "mspaint"
1. Open up your picture.
2. Click on IMAGE
3. Select ATTRIBUTES
THERE YOU WILL SEE THE SIZE REPRESENTED IN PIXELS.
4. CHANGE THE NUMBERS IN THE BOXES FOR WIDTH & HEIGHT.
ENTER THE 480 X 640 RATIO (FOR LANDSCAPE)
ENTER THE 640 X 480 RATIO (FOR PORTRAIT)
"Save as" the picture to new location and name
(you always want to keep your original picture unmodified)