Phalcon Imagick or GD Transparent PNG


I want to convert my PNG images to JPG but my PNG images are transparent. How can I do to color the background in white for all PNG ? Actually I'm using $image->background('#FFFFFF') but my background is black.

Do you have any solutions to remove this alpha ?

You could change the background color of all of those PNG images in an editor like Photoshop or Gimp. Is white what you want or black?