Embodiments may be implemented by a computing device, such as a head-mountable display or mobile phone, in order to pre-emptively warm up the device's camera, when it is probable that a user will be taking a photo. An illustrative method involves a computing device (a) receiving sensor data from one or more sensors associated with the computing device, wherein the computing device comprises an image-capture device, (b) analyzing the sensor data to detect at least one pre-image-capture signal, wherein the at least one pre-image-capture signal indicates a subsequent image-capture signal is likely to be received, and (c) in response to detecting the at least one pre-image-capture signal, causing the computing device to initiate an image-capture preparation process that prepares the image-capture device to capture an image.