How to check a PNG for grayscale/alpha color type?

Question

PHP and GD seem to have trouble creating images from PNGs of type greyscale with alpha when using imagecreatefrompng(). The results are incredibly distorted.

Answer 1

see this answer :

Another usefull note for those using ImageCreateFromPng: PHP and GD do not recognize grayscale/alpha images.

So if you use grayscale images with transparency between 0% and 100%, then save the image as RGB.

At least this is true for PHP Version 4.4.2-1 and in 5.1.2-1 with pictures made with GIMP 2.2.8.

url : http://php.net/manual/en/function.imagecreatefrompng.php