launch-image

    UIImage *image;
    
    NSMutableString *imageName = [[NSMutableString alloc] initWithString:@"Default"];
    
    BOOL isPad = ( UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad );
    
    if( isPad )
    {
        BOOL isLandscape = UIInterfaceOrientationIsLandscape([[UIApplication sharedApplication] statusBarOrientation]);
        NSString *imageOrientation = (isLandscape) ? @"Landscape" : @"Portrait";
        
        BOOL isRetina = ([[UIScreen mainScreen] respondsToSelector:@selector(scale)] && [[UIScreen mainScreen] scale] == 2.0);
        NSString *scaleString = (isRetina) ? @"@2x" : @"";
        
        // Default-Landscape~ipad.png
        // Default-Landscape@2x~ipad.png
        // Default-Portrait~ipad.png
        // Default-Portrait@2x~ipad.png
        imageName = [NSMutableString stringWithFormat:@"%@-%@%@~ipad.png", imageName, imageOrientation, scaleString ];
        
    } else {
        
        if( CGRectGetHeight(self.view.frame) > 480.f)
        {
            // Default-568h.png
            imageName = [NSMutableString stringWithFormat:@"%@-568h.png", imageName];
        } else {
            // Default.png
            // Default@2x.png
            imageName = [NSMutableString stringWithFormat:@"%@.png", imageName];
        }
    }
    
    image = [UIImage imageNamed:imageName];

http://stackoverflow.com/questions/10122750/ios-5-1-and-default-png