Google Images, Morality and Expression

[DynaPass]

I have seen this come up from time to time about using images from a Google Image search. However I have not heard from anyone about taking those images and editing/combining them to create new images and using those on your website.

Although I do not look to find legal advice about doing this I was wondering where this lands in the view of morality. Is it immoral to use someones image to create a new image and use it without credit? Wouldn't this be a form of expression in some ways? Maybe on a non-profit type site...

What are your views about this warriors? Does the image have to be changed a certain amount or can only a piece of the large image be used?

If anyone does have some insight about the legal issues involved with using edited copyrighted images that would be nice as well.