This shows harmony because all the colours used are from the same colour pallet, making the image look unified. It also looks unified because all the elements relate to one another.
Both show emphasis with the usage of colours. They both have dark background (grass, grayscale water/sky), and then a usage of a bright colour- like the yellow flower and red lighthouse. This creates a focus on that element.
All of the above images shows the contrast between big and small. The first one shows the difference of size between the big pumpkin bowl and a much smaller version of the same bowl. The second image shows the difference in size between human hands and two porcupine.
The first image shows rhythm because it is a repetition or pattern of the same image creating movement. The second image is: in the artists' eyes, the lines of red and yellow are used to create the fast movements of cars on a road.
Shape is shown in both of these pictures. In the first one is a set of stars creating a festive feeling, and the other shows how different types of shapes can be used in design.
The first image shows line being used to create a fun, bright picture. While, the other one the different types of lines that can be drawn to create different types of emotions.