1. A method for analyzing skin conditions associated with a subject, performed on a system having a portable image acquisition device, a processor and a memory storing one or more programs for execution by the processor to perform the method comprising: acquiring a first white-light image and a first UV image of at least a portion of a body surface of the subject at the portable image acquisition device, the first white-light and UV images including a plurality of pixels, the pixels in the first white-light image corresponding to respective pixels in the first UV image; sending the first white-light image and the first UV image to the processor for analysis; and at the processor, generating a skin mask having a plurality of elements corresponding to respective pixels in the first white-light image and having been assigned a value; analyzing properties of pixels in at least the first white-light image to identify skin pixels in the first white-light and UV images, wherein the step of identifying comprises, for a pixel in the first white-light or UV image, determining if the pixel is a skin pixel by looking up the value in a corresponding element in the skin mask having said assigned values; and obtaining results associated with at least one skin condition using information in the skin pixels in at least one of the first white-light and UV images.