im_remosaic(3)
works rather as im_global_balance(). It takes apart the mosaiced image in and
rebuilds it, substituting images.
Unlike
im_global_balance(3)
images are substituted based on their filenames. The rightmost occurence of
the string old_str is swapped for new_str, that file is opened, and that image
substituted for the old image.
It's convenient for multispectral images. You can mosaic one band, then use
that mosaic as a template for mosaicing the others automatically.