Do we need to show splash screen while navigating from secondary tiles? Because the application is opening with new instance. Note: In Windows phone Certification Requirements it stats that 'The app may provide a splash screen image in a file called SplashScreenImage.jpg in the root of the XAP package while the app is still trying to load'.
The certification requirements will not require you to manually display a splash image. The splash image, SplashScreenImage.jpg as you mentioned, is displayed automatically by the OS, and is not something you need to worry about handling manually.