choosefile
Open a dialog that prompts the user to select a file.
filename=choosefile(description, extensions)
filename=choosefile(description, extensions,mode)

Inputs
description	A short description of the file types to be selected by the user.
extensions	The extensions of the file types to be selected by the user. The extensions should only contain the suffix of the file type without the leading period.
mode	If it is the string "w" , the file save dialog is displayed. Otherwise the file open dialog is displayed.
Outputs
filename	Name of the file selected by the user, or null if the none was selected.

Description
f=choosefile("Image File",{"gif","jpg"}) will prompt the user to select a file of the type *.gif or *.jpg .