This example of photomontage works well because it is visually interesting and has a lot of contrast. The photo of the woman is in black and white while the photo of the plant is shown in color this contrast makes the image stand out more.
Striking juxtaposition shown in cdv photo of a pug sitting and a retriever lying down in a photographer's studio. Gorgeous photo by Robert Everest, Connaught House, 53 Chapel Road, Worthing. From bendale collection