Visual propaganda has been found to be the most effective and persuasive method of propaganda since World War I.
prop·a·gan·da
information, especially of a biased or misleading nature, used to promote or publicize a particular political cause or point of view.
Visual propaganda has been used since before World War I, however, it had a major impact during both World War I and World war II. Visual propaganda has mainly been used throughout history to achieve a similar purpose, to improve support for war. However, different individuals and organizations have all used different aspects of rhetoric to achieve their purpose.