A method of transmitting an image from a remote server to a portable device and dynamically viewing, by a human observer, the transmitted image on a display of the portable device. On a remote server, a master set of data representative of a graphic image (30) is processed to form a first subset of data representative of a portion of the graphic image. The data is transmitted to the portable device (49) and drawn on the display (34). The user selects a portion of the image to be further expanded and the master database is again processed to form a second subset of data representative of the selected portion of the image. The second subset of data is transmitted to the portable device and drawn (36) on the display.