Improve title bar

android/gradle.properties

 org.gradle.jvmargs=-Xmx1536M
 android.useAndroidX=true
 android.enableJetifier=true
-app.versionName=0.0.24
-app.versionCode=24
+app.versionName=0.0.25
+app.versionCode=25

lib/screens/home.dart

@@ -109,14 +109,29 @@ class Home extends StatelessWidget {
   }
 
   FlatButton _buildTilesetSizeSelectorItem(Data myProvider, int value) {
-    String text = value.toString()+'x'+value.toString();
+    String assetName = 'assets/game/difficulty_' + value.toString() + 'x' + value.toString() + '.png';
+
+    Color borderColor = Colors.blue;
 
     if (myProvider.tilesCount == value) {
-      text = '['+text+']';
+      borderColor = Colors.white;
     }
 
     return FlatButton(
-      child: Text(text),
+      child: Container(
+        decoration: BoxDecoration(
+          borderRadius: BorderRadius.circular(4),
+          border: Border.all(
+            color: borderColor,
+            width: 4,
+          ),
+        ),
+        margin: EdgeInsets.all(8),
+        child: Image(
+          image: AssetImage(assetName),
+          fit: BoxFit.fill
+        ),
+      ),
       onPressed: () { myProvider.updateTilesCount = value; },
     );
   }

pubspec.yaml

@@ -20,5 +20,6 @@ flutter:
   uses-material-design: true
   assets:
     - assets/files/
+    - assets/game/
     - assets/images/
     - assets/ui/