Using GIMP you can convert the white in a PDF to the alpha channel making it transparent. You can then copy/paste the result into the image you are composing. I'm sure you can do the same with Photoshop.
Using GIMP you can convert the white in a PDF to the alpha channel making it transparent. You can then copy/paste the result into the image you are composing. I'm sure you can do the same with Photoshop.