cub2pngs
From VoxBoWiki
cub2pngs will convert any recognized 3D volume to a directory of PNG files (one per slice). Here's the help:
VoxBo cub2pngs (v1.8.5pre8/May 6 2010) summary: convert any 3D image to a directory of PNG images usage: cub2pngs <cubename> <directory> [stem]
