What is "Copying"...

Thanks. That helps a little, but since we've already established that there are exceptions, it doesn't go very far toward proving that in general one doesn't need permission to create (and not distribute) a derivative work. The refrigerator photo could be an application of the fair use exception in copyright.

I also think it's strange that taking a photo of a painting is creating a derivative work as opposed to making a straight-up copy (like photocopying a book), but I'll take your word for it. I guess there is some art involved in taking the photo and that may make the difference.

You piqued my interest in the application of copyright to photography enough to read the web page you cited, and happened to come across this, giving more weight to the proposition that you do generally need permission to create a derivative work:

One of the exclusive rights of a copyright owner is the right to create derivative works from his work – that is, new works based upon or adapted from the original work. You should take care when you digitally manipulate other’s images, as this is likely to be a copyright infringement unless you have obtained the copyright owner’s prior permission.