Selected image of UITabBarItem does not fit the size of tab Swift iOS8+

Question

I am trying to implement an UITabBarController with 2 UITabBarItems . I added in storyboard the TabBarController. I have on important issue with selectedImage property of UITabBarItem class.

The width of selectedImage does not fit the tab. I changed between devices, and for every device the selected image is over the other tab, or does not fit the current tab. (I found a solution: to have the same image but with different width for every device. But for sure this is not a good solution)

The selected image is that one with orange line in the buttom.

Any idea ? Many thanks.

EDIT - Code updated Here is the code which I implemented so far in class MMHomeVC: UITabBarController:

if let arrTabBarItems = tabBar.items {
        var tabBarItem1 = arrTabBarItems[0] as! UITabBarItem
        var tabBarItem2 = arrTabBarItems[1] as! UITabBarItem

        let imgHome         = UIImage(named: "btnHome")?.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal)
        let imgProfile      = UIImage(named: "btnProfile")?.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal)
        let imgSelectedTab  = UIImage(named: "selectedTab_imgBackground")?.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal)
        let imgHomeTabSelected  = UIImage(named: "tabHome_selected")?.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal)
        let imgProfileTabSelected  = UIImage(named: "tabProfile_selected")?.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal)

        tabBarItem1.image = imgHome
        tabBarItem1.selectedImage = imgHomeTabSelected

        tabBarItem2.image = imgProfile
        tabBarItem2.selectedImage = imgProfileTabSelected
}

I played with AlwaysOriginal and Automatic but no success.