[Plugin: Magic Fields] Renaming of Images upon upload

I’m playing around with Magic Fields for the first time and it’s really incredible. Got an issue though involving the renaming of image files upon upload. I have a JQuery script that is supposed to allow you to have a rollover image so I have two images: image.png and image_f2.png. The script looks for the name of the file up until the _f2.png and then uses its matching counterpart that has the _f2.png extension to allow for the rollover. However, MF adds a series of numbers to each file and it’s always different. So instead of image.png and image_f2.png, I’m stuck with possibly 1284327994image.png and 1284328001image_f2.png and thus the script doesn’t work. No rollover. How can I stop it from renaming my files so my script works?