http://scott.sherrillmix.com/blog/programmer/converting-eps-to-png-easily/

You can use ImageMagick to convert EPS file to PNG format easily. Simply

convert Img.eps Img.png

This will give you the png file with DPI 72. If you want to set the DPI for your png file, use

convert -density 300 Img.eps Img.png,

then an image with DPI 300 would be generated.

To process a batch of files, you can simply use command mogrify. For example,

mogrify -format png -density 300 *.eps