1. A computer readable medium having stored thereon one or more sequences of instructions for causing one or more microprocessors to perform the steps for analyzing a portion of the content of a digital image the steps comprising: obtaining a set of image processing instructions, wherein the image processing instructions carry out an analysis of the content of a digital image; retrieving a first sub-region of the digital image from a data storage area; executing the set of image processing instructions to analyze the first sub-region; retrieving a second sub-region of the digital image from the data storage area; executing the set of image processing instructions to analyze the second sub-region; combining the results of the image processing on the first sub-region and the image processing on the second sub-region to provide an analysis of a portion of the digital image.