Here's an example.
An architect appoints a photographer to take some photos of one of their designed and newly built houses. They are extremely happy with the outcome and share, at no fee, the photographs with the builder who then posts them onto his web site.
The architect has paid for the photos and therefore feels they own them.
Unfortunately whilst the architect is trying to be nice and sharing the images with the builder, they are now in breach of copyright. They have no right to pass on the images whether a fee is paid or not.
In Australia the copyright is automatically held by the photographer. There is no requirement to put the copyright symbol on the images, although that can help highlight it in advance.
The photographer provides a license to the architect to use the images for the promotion of their business. They have no right to pass the images onto third parties, alter the images, charge for them or give them away. They do not own them. They have a right through the license to use them for the agreed purpose of promotion of their business.
Even if the photographer does not make this clear when quoting, the law still states that copyright remains with the photographer unless there is a specific agreement to hand copyright over. (Which is highly unlikely, as the photographer can then no longer use the images for the promotion of their business or otherwise).
In this example the architect should have communicated with the photographer and asked what the procedure would be for the builder to utilise them. In most cases the photographer will be more than happy to have the builder pay a small fee for the use of some or all of the images.
Think of it like this. You can't go an buy a painting and then take a photograph of it, and sell the prints. It works exactly the same.
Photographers have a program to embed code into images and can see where on the web they show up.
If you are unsure, just ask the photographer and get any agreement in writing.
There is more information at www.copyright.org.au