If you have a linux system with ImageMagick installed this is easy.
While I refer to jpg and eps files in this howto, conversion between any two formats that ImageMagick supports is similar.
Let us say you have a directory full of eps files along with non eps files. A simple shell script using "sed" will do the trick
for i in *.eps
prefix=`echo $i | sed 's/\.eps//'`
convert -density 300 -units PixelsPerInch $i $newfile