When I use Imagick in PHP to resize PNG images, the output images are black. This is not the case when I resize JPGs; the PHP procedure (provided below) works perfectly for JPGs, so I suspect there's a missing step when processing PNG files.
I've first tested the conversion using ImageMagick on my local computer using this command:
convert x.png -resize 528 -filter Lanczos x-resized.png
...and it works; the resulting PNG file displays and is resized appropriately.
However, when I attempt to do the same on my server (both localhost and live), the result is a black image.
The PHP code I'm using is:
$source = "x.png" // I provide the complete path in my routine, etc.
$destination = "x-resized.png" // likewise.
$im = new Imagick();
$im->readImage($source);
$im->setImageFormat("png");
$im->resizeImage(528, null, Imagick::FILTER_LANCZOS, 1);
$im->writeImage($destination);
$im->clear();
What am I doing incorrectly?
