Horizontal images are best used:
- When the subject is horizontal
When your subject is wider than it is tall, a horizontal image compliments the subject.
- To allow the subject to move horizontally
When your subject is moving from one side of the frame to the other, using a horizontal format in conjunction with the rule of thirds visually allows the subject room to continue moving. This will amplify the sense of motion in the image. This is also true of subjects looking to the side. Having open space to the side allows the subject's gaze to continue farther than is possible in a vertical image.
- To convey a sense of space
Horizontal images can be used to suggest a sense of largeness in landscapes. If a small subject is placed in a large field they can also be used to suggest loneliness.