Firstly the law is very clear: any image will be protected by copyright. Old images (70 years after the death of the creator) may be out of copyright but that rarely applies generally, and not to the case discussed here. It should be assumed that any image is protected by copyright and will need permission to use it.
What is less clear to those unfamiliar with copyright law is the assignment of copyright when commissioning a professional photographer, and how that affects the use of the images delivered by the individual or business that commissioned them.
Again the law is very clear: in the first instance the creator (i.e. the photographer) is the owner of the copyright. If the image is created by an employee as part of their work then the employer owns the copyright. So if you commission a professional photographer to create images for you then the photographer owns the copyright to the images, and no one else can use them.
So how is this dealt with? There are two main options. As part of the contract the photographer can transfer copyright to the business or individual that commissioned the images, or the photographer retains the copyright and gives the client a licence to use the images in certain ways, media and over a period of time. The standard form of contract is the later, for a number of reasons.
The photographer needs to protect their rights and ensure that the fee charged to the client reflects not only the costs of production and profit, but also the value of the images to the business or individual that has commissioned them. This important point has become blurred in the digital age with the internet, social media, mobile phone cameras, and the vast increase in images being created and shared. When initially entering a contract with a professional photographer there will be a brief, hopefully a shot list of some form, time on site or in the studio, and expenses. These are covered in a quote or estimate as required. The usage of the images is also important: are they for use just on the web; small print such as brochures; posters or large format displays; PR use for distribution to news and other media; marketing; or a combination of all these.
As part of the contract between the photographer and client the usage will be agreed and forms the licence to use the images. The licence protects both the client and the photographer. The business that has commissioned the images can use them as agreed, and will also be assured that the photographer can not sell them to another business (at least for any time limit specified). The photographer is protected knowing that the images will only be used as specified and charged for. Why not just transfer copyright? For the photographer that will transfer all rights to the image, with no protection against future use and value in the images. If the copyright is transferred to the client that has commissioned the images then that owner can not only use the images for the initial purpose but could also sell them on to other businesses that will profit from them, sell them on stock image sites, etc. That is a separate business in its own right. Transferring copyright will usually incur a separate fee to the original commission.
Photography as a business requires contracts and terms & conditions as with any other business. When a client commissions a professional photographer to create images there will be a clear agreement about what the client is paying for, and part of that is the use of the images. The photographer is not just charging for time at the shoot, but the running of the business, the equipment, the pre- and post-production, delivery of images etc. Most importantly the client is paying for the photographer's creativity, and that has a value, and the client is getting a product that has a value to the business beyond the simple time taken to shoot the images. Copyright, licensing and the contract work together to ensure both the client and the photographer receive the benefit of the commissioned images.
For more information about copyright see the copyright notice below from the Intellectual Property Office.