In one arrangement, a smartphone camera gathers skin imagery while controlled spectral illumination is emitted from the smartphone display. In a particular embodiment, differently colored bands move across a darkened screen to illuminate the skin from different angles as plural images are being captured. The collection of imagery from different viewing angles, with different spectral illumination, and different illumination angles, can provide imagery (including composite imagery) useful in manual or automated dermoscopic analysis. A great variety of other features and arrangements are also detailed.