Warning: This function is
currently not documented; only the argument list is
available.
Warning: This function is
EXPERIMENTAL. The behaviour of this function, the
name of this function, and anything else documented about this
function may change without notice in a future release of PHP.
Use this function at your own risk.
This method can be used to query image width, height, size, and
format without reading the whole image to memory.
Return Values
Returns TRUE
on success.