It seems like you have the same image resource in two files OR you added an additional, non-required file to the res folder. Rename or remove the other. You can check the required structure of the res folder and subfolders by downloading a fresh copy of WebViewGold from CodeCanyon.
Moreover, please go to the Build drop-down menu in the menu bar. You can see the Rebuild Project under the Clean Project. If you can’t find Rebuild Project, you can use Clean Project instead. Try to build the app again afterward.