1. A portable digital camera device having no photographic film, comprising: a digital image capturing apparatus including an image sensor for capturing a main image including a face, and for acquiring reference image data at least approximately of said same scene as the main image including said face; a dedicated hardware subsystem which is provided reference image data directly from the image sensor; a face filter for identifying a face region within the main image based on analysis of the reference image data; a main system memory which receives raw image data and metadata as implemented by the dedicated hardware subsystem, the main system memory being configured to receive metadata that comprises one or more identified face regions within the main image; and a subsampling module for changing a degree of subsampling that is determined based on a complexity of calculation for said face filter.