Toolbar item image showing as blue square in iOS - works in Android

I have been developing a Xamarin forms project and can't get my ToolbarItem to show my log out image. The image shows up fine in Android but in iOS it just comes up as a blue square. This may be a separate issue but clicking the log out button also will not show my notification, although that part works in Android also.

string logOutButton = Device.OnPlatform("Logout2.png", "Logout.png", "Logout.png");
home.ToolbarItems.Add(new ToolbarItem("Filter", "logOutButton", async () =>
                    {
                        var close = DisplayAlert("Confirm Logout", "Are you sure you want to log out?", "Yes", "Cancel");
                        if (await close) Navigation.PopModalAsync();
                    }));

I attached Logout2.png so you can see the image I am trying to use