PHP: How to draw an image over another image?

Question

I am using PHP & GD library.

I want to draw an image (say this one: http://www.gravatar.com/avatar/107f2fafb2d29fedc3783b141139a878?s=128&d=identicon&r=P

Answer 1

imagecopy() or imagecopymerge(). It's documentation brings exemples too.