diff --git a/mainwindow.cpp b/mainwindow.cpp
index 517f68e..2c297e3 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -12,6 +12,7 @@
 #include <QScrollBar>
 #include <QTimer>
 #include <QEvent>
+#include <QItemSelectionModel>
 #include <iostream>
 
 MainWindow::MainWindow(QWidget *parent)
@@ -82,20 +83,10 @@ void MainWindow::setupConnections()
             });
 
     connect(m_listView, &QListView::clicked, this,
-            [this](const QModelIndex &index)
-            {
-                QString path = m_imageModel->filePath(index);
-
-                QImageReader reader(path);
-                reader.setAutoTransform(true);
-                QImage image = reader.read();
+            [this](const QModelIndex &index) { showPreview(index); });
 
-                m_previewLabel->setPixmap(
-                    QPixmap::fromImage(image).scaled(
-                        m_previewLabel->size(),
-                        Qt::KeepAspectRatio,
-                        Qt::SmoothTransformation));
-            });
+    connect(m_listView->selectionModel(), &QItemSelectionModel::currentChanged,
+            this, [this](const QModelIndex &current) { showPreview(current); });
 
     connect(m_listView->verticalScrollBar(), &QScrollBar::valueChanged,
             this, [this]()
@@ -130,3 +121,21 @@ void MainWindow::loadVisibleThumbnails()
     std::cout << "loadVisibleThumbnails: " << first << " - " << last << "\n";
     m_imageModel->requestThumbnails(first, last);
 }
+
+void MainWindow::showPreview(const QModelIndex &index)
+{
+    if (!index.isValid())
+        return;
+
+    QString path = m_imageModel->filePath(index);
+
+    QImageReader reader(path);
+    reader.setAutoTransform(true);
+    QImage image = reader.read();
+
+    m_previewLabel->setPixmap(
+        QPixmap::fromImage(image).scaled(
+            m_previewLabel->size(),
+            Qt::KeepAspectRatio,
+            Qt::SmoothTransformation));
+}
diff --git a/mainwindow.h b/mainwindow.h
index f801f66..7b01b44 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -19,6 +19,7 @@ private:
     void setupUi();
     void setupConnections();
     void loadVisibleThumbnails();
+    void showPreview(const QModelIndex &index);
 
     bool eventFilter(QObject *obj, QEvent *event) override;
 
diff --git a/thumbnailworker.cpp b/thumbnailworker.cpp
index 1ac22d2..9b094ba 100644
--- a/thumbnailworker.cpp
+++ b/thumbnailworker.cpp
@@ -1,5 +1,6 @@
 #include "thumbnailworker.h"
 #include <QImageReader>
+#include <QPainter>
 
 ThumbnailWorker::ThumbnailWorker(const QString &path,
                                  int row,
@@ -26,13 +27,18 @@ void ThumbnailWorker::run()
 
     if (!image.isNull())
     {
-        // Scale to cover the 128x128 area, then center-crop
+        // Scale to fit within 128x128 keeping aspect ratio
         QImage scaled = image.scaled(128, 128,
-                                     Qt::KeepAspectRatioByExpanding,
+                                     Qt::KeepAspectRatio,
                                      Qt::SmoothTransformation);
-        int x = (scaled.width()  - 128) / 2;
-        int y = (scaled.height() - 128) / 2;
-        QImage thumb = scaled.copy(x, y, 128, 128);
+        // Center on a 128x128 canvas with transparent/white fill
+        QImage thumb(128, 128, QImage::Format_ARGB32_Premultiplied);
+        thumb.fill(Qt::transparent);
+        int x = (128 - scaled.width())  / 2;
+        int y = (128 - scaled.height()) / 2;
+        QPainter painter(&thumb);
+        painter.drawImage(x, y, scaled);
+        painter.end();
         emit finished(m_row, thumb);
     }
 }