Create thumbnails of images

Hello, We have a user account system where the users can upload photos of themselves. We need someone to write a script that will resize and save their uploaded image to both 125x125 and 60x60 sizes. We will need this script added to the upload forms on both the sign up page, and update photo page. We will also need all current uploaded pictures (about 150) resized as well. Please let us know if you have any questions. Thanks.