In the present article we analyze the relationship between ambient illuminations and psychological effects while viewing still images displayed on a liquid crystal display (LCD). In two experiments, six kinds of images were displayed on the LCD under different brightness of illumination conditions and were rated by 15 observers, and four kinds of images were displayed under different colors of illumination conditions and were rated by 27 observers. The semantic differential method and factor analysis method are introduced to analyze the subjective evaluation. It is shown that comfort in viewing is enhanced according to the increase in brightness of the ambient illumination. Particularly, realistic sensation and dynamism are enhanced while retaining comfort with the illumination behind the LCD. It is also shown that realistic sensation and dynamism and comfort are enhanced under the illumination of average chromaticity of displayed images.