It is illegal if you do not have permission from the owner of the images. When I first started making bottle caps I saw a pic of a deer on the internet that I wanted to use. I contacted the owner of the pic to get permission to use it. He okayed it but I had to send him some bows which was fine. Now I use pics of my own deer that I have here in our pens.
Places like Disney, etc DO NOT give anyone permission to use their images. People chose to do it illegally and if caught and do not remove their items can be prosecuted. It is not worth the risk to take. You are better off joining a bottle cap yahoo group and learn how to create your own images. Trust me, once you learn how to do them yourself you feel so much better knowing it is your own work and not someone else's. If you need a link to one of the groups just PM me and I will direct you that way.