Extracts BMP (image) files from ICO (Windows Icon) files.

USAGE:
ico2bmp source_file.ico [destination_dir]

destination_dir is optional and can be left out in which case the BMPs will be
extracted into the current directory.

Extracted BMPs will have names of the form:
source_file_0.bmp
source_file_1.bmp
source_file_2.bmp
etc.

BUGS:
None known.