public AnchorPane topLeft() {
        Rectangle rectangle = new Rectangle();
        rectangle.autosize();
        rectangle.setWidth(240);
        rectangle.setHeight(240);
        rectangle.setFill(Paint.valueOf(Color.WHITE.toString()));
        rectangle.setStroke(Paint.valueOf(Color.GRAY.toString()));
        rectangle.setStrokeWidth(1.0);
        rectangle.setStrokeType(StrokeType.INSIDE);

        Label label = new Label("Quelldatei:");
        label.setLabelFor(rectangle);
        label.getStylesheets().add("labelstyle.css");

        HBox file1 = new HBox();
        file1.setSpacing(10);

        final TextField sourceField = new TextField();
        sourceField.setMinWidth(170);
        sourceField.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent actionEvent) {
                if (checkPath(sourceField.getText(), true) && isPNG(sourceField.getText())) {
                    sourcePath = sourceField.getText();
                    setSourccePreview();
                } else {
                    showWarning("Datei nicht gefunden");
                }
            }
        });

        Button chooseSource = new Button("...");
        chooseSource.setMaxWidth(25);
        chooseSource.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent actionEvent) {
                FileChooser chooser = new FileChooser();
                chooser.getExtensionFilters().addAll(
                        new FileChooser.ExtensionFilter("PNG Images", "*.png")
                );
                File source = chooser.showOpenDialog(primStage);
                if (source != null) {
                    sourcePath = source.toString();
                    sourceField.setText(sourcePath);
                    setSourccePreview();
                }
            }
        });
        file1.getChildren().addAll(sourceField, chooseSource);

        StackPane imageView = new StackPane();
        Rectangle rectangle2 = new Rectangle();
        rectangle2.autosize();
        rectangle2.setWidth(152);
        rectangle2.setHeight(152);
        rectangle2.setFill(Paint.valueOf(Color.WHITE.toString()));
        rectangle2.setStroke(Paint.valueOf(Color.GRAY.toString()));
        rectangle2.setStrokeWidth(1.0);
        rectangle2.setStrokeType(StrokeType.INSIDE);
        imageView.setAlignment(Pos.CENTER);
        imageView.getChildren().addAll(rectangle2, sourceView);


        AnchorPane topLeft = new AnchorPane();
        topLeft.setLeftAnchor(label, 5.0);
        topLeft.setTopAnchor(label, 0.0);
        topLeft.setTopAnchor(rectangle, 9.0);
        topLeft.setTopAnchor(file1, 22.0);
        topLeft.setLeftAnchor(file1, 11.0);
        topLeft.setTopAnchor(imageView, 70.0);
        topLeft.setLeftAnchor(imageView, 44.0);
        topLeft.getChildren().addAll(rectangle, label, file1, imageView);

        topLeft.setPrefHeight(250.0);

        return topLeft;
    }