Macro for cropping pictures

[Frank Kujawski]

  My digital camera has an option to take 16 consective pictures and drop
them in one frame.  Every time it does this the dimensions are always the
same.  Is there a way a macro can be written to chop up the picture and
make an animated sequence?  I would like to do this at the command line.
  About all I do with gimp is to crop and save pictures.  So this is a bit
above my head.
        Frank