A postcard ‘craze’ engulfed the developed world and colonial world during the end of the nineteenth and the beginning of the twentieth century, when over 2.3 million picture postcards were mailed in 1904 alone. Formally published picture postcards can provide a rich source of information for heritage studies as they depict landscape scenery, towns, individual buildings and public plantings such as parks. The evidentiary value of late nineteenth and early twentieth century postcards depends on the veracity of the depicted image. While based on photographs, processes of postcard production allowed the publisher to modify the original imagery to improve the messaging entailed in the image. Modes of image manipulation, such as retouching, can sufficiently alter the content of the image to create limitations to using published postcard imagery as a tool for historic landscape and building analysis. This is the first paper to systematically discuss the process of postcard production and the manipulation of images depicted on the view size of picture postcards. It demonstrates that where evidentiary emphasis is placed on postcard images, it is imperative that a systematic search for variants is carried out.