The use of lines in art and design is well established within the principles and elements of basic design.
Incorporating the use of lines in the artwork you select for your home adds impact to the overall design of a room. Sometimes the impact is bold and obvious. Other times it can be subtle and create a suggestion of added height or expanse. For example, in a small room you can add a perception of height to that space by using vertical lines. Instead of choosing one large horizontal photograph to hang over your couch consider adding three vertical images. If you choose images such as those of Eucalyptus trees shown here where the photos also contain vertical lines you are re-enforcing that impact.
It is a small choice in your room design considerations. But it can add a feeling of balance and impact.