As clear as "can I take a copyrighted photo, use a photoshop filter on it, and then it's not copyrighted anymore?" is pretty clearly a solved question in any copyright system.
I think that this is actually a complex topic in copyright law that requires case by case analysis. It clearly is possible to cut out things from magazines, glue them together to form a collage and create a copyrighted work of art. In my naive opinion sufficient photoshop filtering can thus create a new copyrighted work.