Free up space for monster sprites?

Hello.

Is there anything I can do to free up the space for monster sprites?

Maybe delete some unnecessary stuff from the rom? Or compress all the existing monster sprites?

Expanding the rom doesn't seem to free up space for the monsters ... Is it possible to use that expanded 1mb for the monster sprites? If so ... that would be heavenly!!

Right now I can only make the monsters smaller so my rom has enough space to save. But by shrinking the images I am using ... they make the monsters not so visible ... I would like to keep them at 96 or 128 pixels. =(