||Look for the file: dlgsplash.bmp in your FS2002/UIRES folder. Make a backup of this file before you change it. If, for example, you are wanting to put the Instructor BMP in its place, then just rename dlgsplashfde.bmp (which is the instructor screen) to dlgsplash.bmp.
Very Important!!: Make sure you only replace it with a BMP file of the same dimensions or else it probably won't work. To convert JPG or JPEG format images to BMP files, you can use the free program 'IMGCONV'.