An imager may include an imaging die that is stacked with an image processing die. The imaging die may generate output signals from received light. The image processing die may process the output signals. Through-silicon vias of the imaging die or solder balls may electrically couple the imaging die to the image processing die and convey the output signals to the image processing die. The imaging die may include a pixel array that generates pixel signals from the received light. The image processing die may generate control signals that control the imaging die and are conveyed to the imaging die over the through-silicon vias or solder balls.