1. A method for generating an output image by reducing the size of an input image, comprising the following steps: determine for a pixel location (i,j) in said output image a corresponding area xy in said input image, fetch the input image area xy pixel values, calculate an output pixel value D ij for said pixel location (i,j) using a size reducing algorithm, and insert D ij in the output image, repeat the steps for other pixel locations (i,j) in said output image, wherein said value Di,j is obtained by adding to the lower resolution background representation A, obtained by processing the amount of area xy pixel data to a single low pass filtered area value, a value obtained by amplifying the MED which represents the pixel value in said input image area that most deviates from said lower resolution background representation A, with a significance factor SF.