Theming has become an art on Android. Changing the look of your device is a complicated process, as sometimes very small elements need to be modified. To accomplish this, many themers often use really advanced graphical tools like Photoshop. But editing elements one-by-one is a time consuming task, so an automated process would be handy.
PNG files used in Android are saved as a NinePatch PNGs, which are a bit different than regular PNGs. The border has to be transparent and use a black one pixel width. In short, they differ. That’s why the batch tool presented by XDA Forum Member F4bioo might be useful.
This Windows-only tool gives themers the ability to work on several .9.png files simultaneously. F4bioo made a short tutorial detailing how to use this tool, along with screenshots and a YouTube tutorial video. 9Compile also has some extra features like InjectTheme, which allows you to apply the changes directly into the APK without breaking zipaligning.
If you are planning to start some theming, you should make your way to the tool thread and download the latest version._________