ImageUtil_unixSourcechop_extension' fname is the same as Filename.chop_extension fname but if fname does not have an extension, fname is returned instead of raising Invalid_argument.
get_extension fname returns the extension of the file fname. If the file does not have an extension, Invalid_argument is raised.
get_extension' fname is the same as get_extension fname but if fname does not have an extension, the empty string is returned and no exception is raised.
Define an output channel for the builtin buffered output on Uix. see ImageChannels for more info