1. A non-transitory computer readable medium having stored therein instructions, which, when executed, cause a processor to perform operations, the operations comprising: receiving image data from one or more image sensors associated with a device; enabling processing of image data from the one or more image sensors in at least first and second modes, the first mode including processing less image data than in the second mode; operating the processing in the first mode; detecting a context-based trigger indicative of an increased likelihood of an expected gesture by a user, wherein the context-based trigger is generated using information other than the received image data; and switching the processing from the first mode to the second mode when the context-based trigger is detected.