A spanking fake is a photograph that has been digitally manipulated to fit a certain spanking fantasy or scenario. They rarely pretend to be 'real' photos, however, usually openly admitting their 'fake' status through labelling/branding by their creators.
The most common form of 'spanking fake' involves altering an existing spanking photograph to depict a well-known celebrity either giving or receiving the spanking (in much the same way as common 'nude fakes' manipulate photos of naked models to resemble celebrities), though fakes are sometimes created to do something as simple as change the spanking implement depicted to a different one. For the case where the gender or apparent age of a person in the image is changed, see gender/age manipulation in spanking art. Some artists specialize in creating complex 'spanking fakes', but many are simply made as tongue-in-cheek 'jokes'.
A simple search on the Internet will turn up popular combinations such as Madonna spanking Britney Spears or Jessica Alba spanking Jennifer Love Hewitt, et al. There are also many manipulated photos that parody political figures such as President Obama spanking Sarah Palin.
Extreme Nude Fakes is a website with a large database of manipulated photos showing popular celebrities being spanked, etc. In addition, the Chross Spanking Blog has a gallery of celebrity spanking fakes.
The creative process can be simply explained as essentially 'cutting and pasting the head from one photo on the body of a spanking model in another', though often the technique is far more complicated than this, with more sophisticated retouching to match lighting, shadows, skin tones, etc.
Artists who created spanking fakes include: