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.
Relationship between life and death. inside, outside: No information about this but it is two different photographs put together to create a half skull, half face image. That heavily relates to the theme of inside, outside and in between.