use smaller shared stage icon to reduce memory usage

src/main/java/com/sparrowwallet/sparrow/AppServices.java

@@ -92,6 +92,8 @@ public class AppServices {
 
     private TrayManager trayManager;
 
+    private static Image windowIcon;
+
     private static final BooleanProperty onlineProperty = new SimpleBooleanProperty(false);
 
     private ExchangeSource.RatesService ratesService;
@@ -498,7 +500,7 @@ public class AppServices {
             stage.setMinWidth(650);
             stage.setMinHeight(708);
             stage.setScene(scene);
-            stage.getIcons().add(new Image(MainApp.class.getResourceAsStream("/image/sparrow-large.png")));
+            stage.getIcons().add(getWindowIcon());
 
             appController.initializeView();
             stage.show();
@@ -509,6 +511,14 @@ public class AppServices {
         }
     }
 
+    private static Image getWindowIcon() {
+        if(windowIcon == null) {
+            windowIcon = new Image(MainApp.class.getResourceAsStream("/image/sparrow-icon.png"));
+        }
+
+        return windowIcon;
+    }
+
     public static boolean isReducedWindowHeight(Node node) {
         return (node.getScene() != null && node.getScene().getWindow().getHeight() < 768);
     }
@@ -694,7 +704,7 @@ public class AppServices {
 
     public static void setStageIcon(Window window) {
         Stage stage = (Stage)window;
-        stage.getIcons().add(new Image(AppServices.class.getResourceAsStream("/image/sparrow-large.png")));
+        stage.getIcons().add(getWindowIcon());
 
         if(stage.getScene() != null && Config.get().getTheme() == Theme.DARK) {
             stage.getScene().getStylesheets().add(AppServices.class.getResource("darktheme.css").toExternalForm());