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The real gratification in writing an Android application comes with publishing it. However, there is plenty of prep work necessary before the author can do that. One of the first things a prospective publisher should consider is what graphics are necessary for the application. Even if there are no graphics in the application, which is the case for all the examples in this tutorial except the map marker, graphics should be included for launch icons at least. The address http://developer.android.com/guide/practices/ui_guidelines/icon_design.html will give you information on the size requirements for graphics for specific purposes such as launch icons, and acceptable formats as well. On this page you will also find a link to a set of templates to work with. A little experience with Photoshop or Gimp is helpful here.