Images are data just as much as any other source, and they are a type of data which can be highly vulnerable to manipulation, alteration and mis-representation.
If your research involves analysing images, then you may wish to take a look at the Image Manipulation webpages from the HEADT (Humboldt-Elsevier Advanced Data and Text) Centre, which offer an overview on contemporary and historical perspectives on image manipulation, and contain examples spanning diverse themes such as race, controversies in contemporary photography, art forgery scandals, and more.