title: create custom intro screen slider in flutter
body: <p>i need to create something like this 
  <a href="https://i.stack.imgur.com/NyoS5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NyoS5.png" alt="intro slider like this"></a></p>
  
  <p>i am using intro slider plugin from flutter but it does not support 2 images
  i have tried </p>
  
  <pre><code> slides.add(
        new Slide(
          pathImage: 'assets/logo_1.png',
          description:
              "Find trusted help for everything on your to-do-list.",
          styleDescription: TextStyle(
            color: Colors.black,
            fontSize: 18.0,
          ),
          marginDescription: EdgeInsets.only(top: 10.0),
          backgroundImage: "assets/ss4.jpg",
          backgroundOpacity: 0.0,
        ),
      );
  
   IntroSlider(
                slides: this.slides,
                colorActiveDot: Color(0xFF17b01b),
                sizeDot: 10.0,
                isShowSkipBtn: false,
                styleNameDoneBtn: TextStyle(
                  color: Color(0xFF17b01b),
                  fontSize: 15.0,
                  fontWeight: FontWeight.bold,
                ),
                nameDoneBtn: 'Got it &gt;',
                nameNextBtn: 'Got it &gt;',
                    onDonePress:this.onDonePress ,
              )),
  </code></pre>
  
  <p>Intro slider support two images but 2nd one is for background image so my image takes full background of screen in intro slider , how can i set 2nd image in center like in image i have attached?
  or how can i give height width to background image in intro slider ??</p>