You can add SplashScreen easily of WPF application.
1-Create image that you want to use as a splash screen.
You can use any image format like BMP, GIF, JPEG, PNG, or TIFF format.
2-Right click on project and click on existing Items then add image to project
3-In Solution Explorer, select the image.
4- In the Properties window of image, click the drop-down arrow for the Build Action property.
Select SplashScreen from the drop-down list.
5- Press F5 , SplashScreen will show before application start.
this is useful when application start-up is slow.