You can re-size pics in the paint program that comes with most computers.

Start-accessories-paint

After you've opened up paint click on file then open and find the name of the pic you want to re-size.

Then click on image and stretch/skew. If the pics are really big put 50% for both horizontal and vertical. (Or you can put whatever you want. You just want them to be the same number so that the pic doesn't get distorted.)

Voila your pics are re-sized.