If i create something in maya i have the full rights to use it... right?

texture-wise - if they are hand painted textures they are mine; if they are copyright/royalty free photos they are ok to use commercially... right?

what if the textures includes a photo which is not copyright free but has been changed a lot so its unrecognisable?

also do you need to do anything -like register or something- to have the copyright for an image/animation you create?