Outputs a GD2 image to the given
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
The path to the saved file. If not set or NULL, the raw image stream will be outputed directly.
Either IMG_GD2_RAW or IMG_GD2_COMPRESSED. Default is IMG_GD2_RAW.
Note: This function requires GD 2.0.1 or later (2.0.28 or later is recommended).
Note: The GD2 format is commonly used to allow fast loading of parts of images. Note that the GD2 format is only usable in GD2-compatible applications.