1. A non-transitory computer readable medium having stored thereon a computer program for execution by a processor configured to perform a method of displaying images of a specimen from a virtual microscope slide data structure, the program comprising: a communications portion configured to retrieve images from the virtual microscope slide data structure, the data structure comprising a first and second set of contiguous non-overlapping images of the specimen, and coordinating information that relates positions of the first and second set of images, wherein a plurality of images in the first set of images are associated with a first focal plane and a plurality of images in the second set of images are associated with a second focal plane, wherein the second focal plane is displaced relative to the first focal plane; a display portion configured to construct a composite image of a portion of the specimen based on at least a portion of the first or second set of images.