1. A computer-implemented method for providing a graphical user interface for enlarging a portion of an image displayed by a web browser, the method comprising: providing a first image from a server system to a client computing device for display; providing a second image from the server system to the client computing device for display; and providing instructions from the server system to the client computing device for displaying a portion of the second image as a plurality of rectangular shapes, and for displaying a window having an opaque curved border that overlaps a plurality of edges of the rectangular shapes to depict the portion of the second image within the window as having a curved perimeter, wherein the portion of the second image displayed within the window corresponds to a position of the window over the first image.