Electronic system and related devices and methods

A wearable device, comprising:

• a watch band;
• a watch body comprising (i) a front face, (ii) a rear face opposite the front face, (iii) a first image sensor in the front face;
• and (iv) a second image sensor in the rear face;
• a coupling mechanism configured to detachably couple the watch body to the watch band;
• one or more processors;
• and
• memory storing one or more programs configured to be executed by the one or more processors, the one or more programs including instructions for:
• detecting, at a first time, that the watch body is coupled to the watch band via the coupling mechanism;
• in response to detecting that the watch body is coupled to the watch band via the coupling mechanism, permitting activation of the first image sensor by a user;
• detecting, at a second time, that the watch body is not coupled to the watch band via the coupling mechanism;
• and
• in response to detecting that the watch body is not coupled to the watch band via the coupling mechanism, activating the second image sensor without user input.

A non-transitory computer-readable medium encoded with instructions that, when executed by at least one computer processor, performs:

• determining at least one computing task;
• determining whether to perform the at least one computing task on a watch body or a head-mounted display (HMD);
• performing the at least one computing task on the watch body or the HMD based on the determination of whether to perform the at least one computing task on the watch body or the HMD;
• sending results of the at least one computing task to the watch body when the HMD performs the at least one computing task;
• and
• sending results of the at least one computing task to the HMD when the watch body performs the at least one computing task.