Include or use the image on any webpage, guestbook, chatroom, or in a book or journal that is to be printed. Post or distribute a modified version of the image. Use whole or parts of the image, in any way, with or without your own modifications, while pretending that it is your own or someone else's work. To get the artist's permission, all you have to do is ask. Usually you will get the artist's consent, as has been done here.
Artists are a friendly and accommodating lot.