diff --git a/viewer/JFJochViewerDatasetInfo.cpp b/viewer/JFJochViewerDatasetInfo.cpp
index 955bdc60..d27f8ecc 100644
--- a/viewer/JFJochViewerDatasetInfo.cpp
+++ b/viewer/JFJochViewerDatasetInfo.cpp
@@ -87,8 +87,10 @@ void JFJochViewerDatasetInfo::datasetLoaded(std::shared_ptr<const JFJochReaderDa
 
 void JFJochViewerDatasetInfo::imageLoaded(std::shared_ptr<const JFJochReaderImage> image) {
     this->image = image;
-    if (image)
+    if (image) {
         chart_view->setImage(image->ImageData().number);
+        grid_scan_image->setImage(image->ImageData().number);
+    }
 }
 
 void JFJochViewerDatasetInfo::imageSelectedInChart(int64_t number) {
diff --git a/viewer/image_viewer/JFJochGridScanImage.cpp b/viewer/image_viewer/JFJochGridScanImage.cpp
index 8ecd8dfa..8cfefdfd 100644
--- a/viewer/image_viewer/JFJochGridScanImage.cpp
+++ b/viewer/image_viewer/JFJochGridScanImage.cpp
@@ -8,6 +8,7 @@ JFJochGridScanImage::JFJochGridScanImage(QWidget *parent) : JFJochImage(parent)
 void JFJochGridScanImage::clear() {
     W = 0;
     H = 0;
+    this->settings = std::nullopt;
     if (scene())
         scene()->clear();
     CalcROI();
@@ -18,6 +19,7 @@ void JFJochGridScanImage::loadData(const std::vector<float> &data, const GridSca
         clear();
         return;
     }
+    this->settings = settings;
 
     W = settings.GetGridSizeX_step();
     H = settings.GetGridSizeY_step();
@@ -112,3 +114,24 @@ void JFJochGridScanImage::mouseDoubleClickEvent(QMouseEvent *event) {
     JFJochImage::mouseDoubleClickEvent(event);
 }
 
+void JFJochGridScanImage::setImage(int64_t val) {
+    if (settings) {
+        current_image_W = settings->GetElementPosX_step(val);
+        current_image_H = settings->GetElementPosY_step(val);
+    } else {
+        current_image_W = -1;
+        current_image_H = -1;
+    }
+    Redraw();
+}
+
+void JFJochGridScanImage::addCustomOverlay() {
+    if (current_image_W < 0 || current_image_H < 0 || current_image_W >= W || current_image_H >= H)
+        return;
+
+    QPen pen(feature_color, 3);
+    pen.setCosmetic(true);
+
+    auto rect = scene()->addRect(current_image_W, current_image_H, 1, 1, pen);
+}
+
diff --git a/viewer/image_viewer/JFJochGridScanImage.h b/viewer/image_viewer/JFJochGridScanImage.h
index e7989531..27b8e4f5 100644
--- a/viewer/image_viewer/JFJochGridScanImage.h
+++ b/viewer/image_viewer/JFJochGridScanImage.h
@@ -12,11 +12,15 @@ Q_DECLARE_METATYPE(GridScanSettings)
 class JFJochGridScanImage : public JFJochImage {
     Q_OBJECT
 
+    std::optional<GridScanSettings> settings;
     std::vector<int64_t> image_index;
+    int64_t current_image_W = -1;
+    int64_t current_image_H = -1;
 
     void mouseHover(QMouseEvent *event) override;
     void mouseDoubleClickEvent(QMouseEvent *event) override;
     void loadImage(QMouseEvent *event);
+    void addCustomOverlay() override;
 signals:
     void imageSelected(int64_t number);
     void writeStatusBar(QString string, int timeout_ms = 0);
@@ -24,6 +28,7 @@ public:
     JFJochGridScanImage(QWidget *parent = nullptr);
 public slots:
     void loadData(const std::vector<float> &data, const GridScanSettings &settings);
+    void setImage(int64_t val);
     void clear();
 };
 
diff --git a/viewer/image_viewer/JFJochImage.cpp b/viewer/image_viewer/JFJochImage.cpp
index bc9e514d..f78025a8 100644
--- a/viewer/image_viewer/JFJochImage.cpp
+++ b/viewer/image_viewer/JFJochImage.cpp
@@ -459,13 +459,6 @@ void JFJochImage::Redraw() {
         setScene(currentScene);
         // Reset initial-fit state for a new scene
         initial_fit_done_ = false;
-        last_fit_W_ = 0;
-        last_fit_H_ = 0;
-    }
-
-    // If image size changed since last fit, allow a new initial fit
-    if (last_fit_W_ != W || last_fit_H_ != H) {
-        initial_fit_done_ = false;
     }
 
     // Restore the zoom level
@@ -701,8 +694,7 @@ void JFJochImage::CalcROI() {
 
 void JFJochImage::fitToView() {
     initial_fit_done_ = false;
-    fitToViewShorterSideOnce();
-    Redraw();
+    updateOverlay();
 }
 
 void JFJochImage::fitToViewShorterSideOnce() {
@@ -733,7 +725,5 @@ void JFJochImage::fitToViewShorterSideOnce() {
     setTransformationAnchor(oldAnchor);
 
     initial_fit_done_ = true;
-    last_fit_W_ = W;
-    last_fit_H_ = H;
     last_fit_viewport_ = vp;
 }
diff --git a/viewer/image_viewer/JFJochImage.h b/viewer/image_viewer/JFJochImage.h
index 423ea1cd..02094c1b 100644
--- a/viewer/image_viewer/JFJochImage.h
+++ b/viewer/image_viewer/JFJochImage.h
@@ -38,7 +38,6 @@ protected:
 
     // Track initial fit state and last image size
     bool initial_fit_done_ = false;
-    size_t last_fit_W_ = 0, last_fit_H_ = 0;
 
     QColor feature_color = Qt::magenta;
     float foreground = 10.0;