A digital camera for capturing and processing images of different resolutions and a corresponding method for down-scaling a digital image are provided. The method includes forming an image of a real scene on an image sensor that is made up of a plurality of pixels arranged in a matrix. The method further includes addressing and reading pixels in the matrix to obtain analog quantities related to the pixels luminance values, converting the analog quantities from the pixels matrix into digital values, and processing the digital values to obtain a data file representing the image of the real scene. To reduce computation time and power consumption, the addressing and reading of the pixels includes selecting a group of pixels from the matrix, and storing the analog quantities related to the pixels of the selected group of pixels into an analog storing circuit. The stored analog quantities are averaged to obtain an analog quantity corresponding to an average pixel luminance value.