ImageMagick help

[Don Calfa]

I'm trying to setup a script that resizes images.  It's for a 
non-computer savvy type of person.  The goal is that they:

1.  Insert the memory card from their camera in the reader
2.  Click a button that removes the files from the card and places them 
on the hard drive
3.  Resizes the images and places those in a different location for 
e-mail purposes.

I need the original filename to be exactly the same as the converted 
filename.  The only variable I've been able to find is %nnd where nn is 
number of decimal places and d is the count of  the images.

convert -size 640x480 *.jpg -resize 640x480 output\%02d.jpg

renames all files to 00.jpg; 01.jpg, 02.jpg, etc...

Google hasn't produced the variable either nor has the imagemagick site. 
 Any help appreciated.