1. A method for performing co-registered optical imaging, the method comprising: acquiring a three-dimensional (3D) surface outline of a subject to be imaged; representing the 3D surface outline as a discretized mesh; using two or more probes of a probe assembly to acquire an optical signal at a surface of the subject, the two or more probes including a first probe and a second probe; tracking one or more markers on each of the two or more probes of the probe assembly to track a position and orientation of each of the two or more probes as the optical signal is acquired by (i) positioning on the first probe a first optical marking element having a first plurality of markers, each of the first plurality of markers having a predetermined, fixed relationship to one another, (ii) positioning on the second probe a second optical marking element having a second plurality of markers, each of the second plurality of markers having a predetermined, fixed relationship to one another, and (iii) providing a tracking receiver to determine a position and orientation of each marker in each of the first and second optical marking elements; receiving, via an imaging system coupled to the probe assembly, the optical signal acquired by the probe assembly; converting the optical signal to image data; and co-registering the image data to the discretized mesh in accordance with the tracked position and orientation of each of the two or more probes to form an image of the subject.