I think your confusing what I said
Most of the time you pay for an image to be made which is exclusive to you.
Meaning you buy the image outright with a license to do with it what you like. THis is the norm for high end production and corporate work.
Where as Hire someone for work means you hire someone to do the job and you can use the work subject to their copyright and licensing, This is the misconception of people hiring photographers etc. They take photos and give you copies normally x amount with the option to purchase more for your sole usage etc. The images still belong to the photographer under copyright unless specifically stated in a contract.
Same goes for art work there are hundreds of variations, commission someone to work for you where basically they become your employee so anything they create is by extension yours as they are working for you.
other variations also include the image is yours to do what you like with as long as you credit the original artist, ie artwork done by Hoogle, or based upon original artwork by Hoogle
or
Here is your image credit me, pay me to use it but if you want to change or have alterations done to it then it can only be done by me etc
As I said though without seeing the contract then it is hard to see what real legality issues may come about here.
I have worked in teams on high end level and have learnt the normal is if your spending a lot of money for a high profile project you normally have buy out contracts.
FOr example Apple can pay me to design a new logo for them I guarantee that the contract will state that apple will own all rights to the image, trademark it and can use it however they see fit. They will also probably make you sign a secrecy contract which makes you forfeit any right to the logo or even telling anyone you designed it, SO to the rest of the world apples logo was designed by Apple no 3rd party.
