The TabBar images are tinted by default. This is a way to use original images.

gistfile1.m

UITabBarController *tabBarView = (UITabBarController *)self.window.rootViewController;
    UITabBarItem *item0 = [tabBarView.tabBar.items objectAtIndex:0];
    item0.image = [[UIImage imageNamed:@"icon-chat"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    item0.selectedImage = [UIImage imageNamed:@"myImage"];