The N73 names its pictures by the date which the picture was taken, followed by the number of the picture taken for the month. There is an option in the camera settings that allows you to disable the date naming option and use text of your choice, such as photo, image, or whatever. If you choose that option, the images you take will be numbered accordingly. I just switched mine from Date to the Text "Image" and the next picture I took was "Image236" because it is the 236th picture I took this month.
