1. A computer-implemented method for displaying a portion of a high-resolution image in the context of a base-resolution image, wherein one or more processors are programmed to perform the steps comprising: receiving a request to view an image at a client device; sending a request to a server over a network for a base-resolution image that corresponds to the requested image; receiving the base-resolution image from the server over the network; displaying the base-resolution image on a display of the client device; receiving a request to display an area of interest of the base-resolution image in high resolution; sending a request to the server over the network for a high-resolution image that corresponds to the base-resolution image; receiving the high-resolution image from the server over the network; and displaying a portion of the high-resolution image corresponding to the area of interest as an overlay of the base-resolution image at a location that corresponds to the area of interest, wherein the overlay comprises a virtual lens, wherein displaying the portion of the high-resolution image corresponding to the area of interest further comprises determining whether at least a portion of the virtual lens would be outside a border of the base-resolution image if the virtual lens were rendered centered over the area of interest; and if at least a portion of the virtual lens would be outside a border of the base-resolution image, determining an offset location for the virtual lens where the virtual lens would not be outside of the border of the base-resolution image; and rendering the virtual lens such that the virtual lens and the portion of the high-resolution image displayed within the virtual lens is centered over the offset location; tracking movements of a cursor controlled by a pointing device over the base-resolution image at the client device; moving the virtual lens with respect to the base-resolution image based on the location of the cursor relative to the base resolution image, the position of the virtual lens being commandable in response to a user action; and updating the portion of the high-resolution image displayed by the virtual lens as the virtual lens moves across the base-resolution image based on the location of the cursor relative to the base-resolution image, wherein updating the portion of the high-resolution image further comprises determining whether an additional portion of the high-resolution image is required for display by the virtual lens; and sending a request to the server for the additional portion of the high-resolution image if an additional portion is required.