Versions
of
GD
older
than
gd-1.6
support
gif
format
images
,
and
do
not
support
png
,
where
versions
greater
than
gd-1.6
support
png
,
not
gif
.
These
functions
do
not
require
the
GD
library
.
This
extension
does
not
define
any
configuration
directives
.
This
extension
does
not
define
any
resource
types
.
These
constants
are
defined
by
this
extension
,
and
will
only
be
available
when
the
extension
has
either
been
compiled
into
PHP
or
dynamically
loaded
at
runtime
.