In additive wavelet transform (AWT) based classical pansharpening methods, the details of the panchromatic (PAN) image added to the multispectral (MS) image directly or by weighting after the detail extraction. In this paper, the details will be weighted during the detail extraction process. The details of the PAN image will be obtained by a weighted additive wavelet transform (WAWT). In order to achieve this aim, the range parameter of WAWT will be optimized for every image. The results obtained by the proposed method are compared with the classical AWT method, the context based method (CBD), and the enhanced CBD (ECB) method. It is observed that the proposed injection approach has better performance than the conventional weighted detail injection schemes.