It's important to keep a constant knowledge of history and what has come before - and decorating a room with posters or pictures from wars past can display both a sense of patriotism and a knowledge of past history. Posters and pictures of World War 1 placed within any room can bring this element into the atmosphere, from old World War I Recruitment Posters which encourage enlistment to various other posters and pictures from World War I.
These posters and pictures from World War I can create an awareness of history and place almost educational opportunities into an area; old black and white photographs of World War I aircraft and World War I bonds posters on the walls will invest a certain sort of knowledge into the air of a room.
Placing these pictures and posters takes some consideration; they can rarely take away from their surroundings and often will serve only in providing contrast of some sort. World War I Red Cross posters on the walls of a study or classroom can create a reflection of the past without having to dive into movies or textbooks.
From an appreciation of military history to world history or just the advancement of technology, posters and pictures from World War I will help to spice up a room - they may fit better with simpler styles or along-side books and other posters with similar subject matter, but will always create their own self-contained atmosphere around them and can serve as fine mementos of history.