(PHP 4 >= 4.3.2, PHP 5)
imageistruecolor() finds whether the image image is a truecolor image.
image
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
Returns TRUE if the image is truecolor, FALSE otherwise.
Замечание: Эта функция нуждается в GD версии 2.0.1 или выше.