PHP+GD: How to do multiply blending when overlaying images?

Question

PHP

There are two pictures: a gray base and a logo with a white background.

The task is to overlay the logo on top of the gray base so that they merge. In the graphics editor, everything seems to be simple: two layers, where Blending mode: multiply is set for the top one with the logo and everything is ready:

How to do this in PHP using the GD library?
The only thing I dug into myself is the option of overlaying a semi-transparent top image on top of the base:

$image_1 = imagecreatefrompng('base.png');
    imagealphablending($image_1, true);
    imagesavealpha($image_1, true);
    imagecopymerge($image_1, $iage_2, 0, 0, 0, 0, 100, 100, 50);

But that's not it at all.

Answer 1

I understand that you want to use this picture as a watermark? www.phpclasses.org/search.html?words=watermark&x=0...