Orthogonal transformation of digital images can be represented as a decomposition over basis matrices or basis images. Grayscale and color basis images are introduced. For particular case of DWT (Discrete Wavelet Transform) obtained basis wavelet images have a block structure similar to frequency bands of the the DWT coefficients. A steganographic scheme for frequency domain watermarking based on this representation is considered. Presented example of detection algorithm illustrates how this representation can be used for frequency embedding techniques.