A user will receive a variation of a particular file depending upon the
type of network the user is currently accessing. More particularly, a
user will typically receive a smaller version of a file when the user is
accessing a low-bandwidth (low data rates) network, and can choose to
receive a larger version of the file when the user accesses a
high-bandwidth (high data rates) network. When several networks are
available to the user either simultaneously or sequentially, the user
will receive the optimum file version based on cost and quality
preferences in the former case and may receive multiple versions of the
file in the later case, each increasing in quality.