diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index a568fc030..14505b792 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog
 ## 1.0.0
+### 1.0.0-rc.166
+* In `jfjoch_viewer`, Alt and the mouse wheel step through the dataset one image at a time.
+
 ### 1.0.0-rc.165
 This is an UNSTABLE release. It includes many experimental features, as well as many AI generated fixes. We recommend using rc.152 for production use.
 
diff --git a/viewer/JFJochViewerWindow.cpp b/viewer/JFJochViewerWindow.cpp
index 3c8cfabb5..215557691 100644
--- a/viewer/JFJochViewerWindow.cpp
+++ b/viewer/JFJochViewerWindow.cpp
@@ -224,6 +224,8 @@ JFJochViewerWindow::JFJochViewerWindow(QWidget *parent, bool dbus, const QString
 
     connect(toolBarImage, &JFJochViewerToolbarImage::loadImage, reading_worker, &JFJochImageReadingWorker::LoadImage);
 
+    connect(viewer, &JFJochDiffractionImage::stepImage, toolBarImage, &JFJochViewerToolbarImage::stepImage);
+
     connect(toolBarDisplay, &JFJochViewerToolbarDisplay::setForeground, viewer,
             &JFJochDiffractionImage::changeForeground);
 
diff --git a/viewer/image_viewer/JFJochImage.cpp b/viewer/image_viewer/JFJochImage.cpp
index e06eb3133..39e4c21ad 100644
--- a/viewer/image_viewer/JFJochImage.cpp
+++ b/viewer/image_viewer/JFJochImage.cpp
@@ -143,6 +143,16 @@ void JFJochImage::setFeatureColor(QColor input) {
 void JFJochImage::wheelEvent(QWheelEvent *event) {
     if (!scene()) return;
 
+    // Alt+wheel steps through the dataset instead of zooming. The view does not know which image
+    // it shows, so the step is emitted and the navigation toolbar applies it.
+    if (event->modifiers() & Qt::AltModifier) {
+        const int delta = event->angleDelta().y();
+        if (delta != 0)
+            emit stepImage(delta > 0 ? 1 : -1);
+        event->accept();
+        return;
+    }
+
     const double zoomFactor = 1.15; // Zoom factor
 
     // Get the position of the mouse in scene coordinates
diff --git a/viewer/image_viewer/JFJochImage.h b/viewer/image_viewer/JFJochImage.h
index 8b43034ca..b8cb6ea67 100644
--- a/viewer/image_viewer/JFJochImage.h
+++ b/viewer/image_viewer/JFJochImage.h
@@ -230,6 +230,8 @@ signals:
     void hoverScenePos(QPointF scenePos);
     // A new frame has been rendered into Frame(). Follower views repaint on this.
     void frameRendered();
+    // Alt+wheel asks for a move through the dataset: +1 one image forward, -1 one back.
+    void stepImage(int steps);
 private slots:
     void onScroll(int value);
 public slots:
diff --git a/viewer/toolbar/JFJochViewerToolbarImage.cpp b/viewer/toolbar/JFJochViewerToolbarImage.cpp
index 1fbddc77e..8ab28efd2 100644
--- a/viewer/toolbar/JFJochViewerToolbarImage.cpp
+++ b/viewer/toolbar/JFJochViewerToolbarImage.cpp
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 
 #include "JFJochViewerToolbarImage.h"
+#include <algorithm>
 #include <QTimer>
 #include "../widgets/ToolbarIcons.h"
 
@@ -176,6 +177,15 @@ void JFJochViewerToolbarImage::leftmostButtonPressed() {
     emit loadImage(0, sum);
 }
 
+void JFJochViewerToolbarImage::stepImage(int steps) {
+    if (image_count_in_dataset == 0)
+        return;
+    const auto target = std::clamp<int64_t>(curr_image + steps, 0,
+                                            static_cast<int64_t>(image_count_in_dataset) - 1);
+    if (target != curr_image)
+        emit loadImage(target, sum);
+}
+
 void JFJochViewerToolbarImage::imageNumberSliderPressed() {
     image_number_slider_manual = true;
 }
diff --git a/viewer/toolbar/JFJochViewerToolbarImage.h b/viewer/toolbar/JFJochViewerToolbarImage.h
index 93792ef2b..88b9b9eb8 100644
--- a/viewer/toolbar/JFJochViewerToolbarImage.h
+++ b/viewer/toolbar/JFJochViewerToolbarImage.h
@@ -57,6 +57,7 @@ public:
     explicit JFJochViewerToolbarImage(QWidget *parent = nullptr);
 public slots:
     void setImageNumber(int64_t total_images, int64_t current_image);
+    void stepImage(int steps);
     void setAutoloadMode(JFJochImageReadingWorker::AutoloadMode input);
     void setHttpConnection(bool connected, QString addr);
 private slots: