1. A method for creating a fused image from an image pair comprising a panchromatic image and a multi-spectral image, comprising: obtaining image data defining a first image of a panchromatic image type, said first image having a first spatial resolution and a first spectral resolution; obtaining image data defining a second image of a multi-spectral image type, said second image having a second spatial resolution lower than said first spatial resolution and a second spectral resolution higher than said first spectral resolution; concurrently calculating a point spread function for down-sampling said first image to said second spatial resolution, and a set of weights for down-sampling said second image to said first spectral resolution, said point spread function and said set of weights specifically optimized to the unique characteristics of the image pair; fusing said first image and said second image to initialize a fused image having said first spatial resolution and said second spectral resolution; using said point spread function and said set of weights to determine scaling factors for scaling radiance value of pixels defining said fused image to provide consistency with radiance value of pixels forming said first image and said second image.