1. A method for adjusting image colors of an image projector, the method comprising the steps of: outputting a white signal to a projection screen; photographing a background color by taking a picture of the projection screen; calculating a chromaticity of an average value of the photographed background color in order to determine if another background color and white color exist; performing a color correction of the photographed background color if another background color exists; and outputting the corrected image to the projection screen in real-time.