1. An image predictive coding method comprising: sampling an image signal into a plurality of blocks; obtaining a quantized DC coefficient and quantized AC coefficients of a current block; adaptively selecting a prediction block for the current block from either an above block or a left block immediately adjacent to the current block; predicting the quantized DC coefficient of the current block from a quantized DC coefficient of the prediction block adaptively selected from either the above block or the left block; and predicting the quantized AC coefficients of the current block from either set of quantized AC coefficients of: (a) a first column of the left block when the left block is selected in the quantized DC coefficient prediction of the current block; or (b) a first row of the above block when the above block is selected in the quantized DC coefficient prediction of the current block.