diff --git a/Photo.cs b/Photo.cs
index 55b1b91..793ec5f 100644
--- a/Photo.cs
+++ b/Photo.cs
@@ -105,6 +105,7 @@ public class Photo {
   public GpsInfo? Gps = null;
   public Rectangle CropRectangle = Rectangle.Empty;
   public Vector2i ViewOffset = Vector2i.Zero;
+  public float Rotation = 0;
 
   private static long touchCounter = 0;
   private Texture texture;
diff --git a/Program.cs b/Program.cs
index 19a87c4..5351f82 100644
--- a/Program.cs
+++ b/Program.cs
@@ -261,6 +261,46 @@ public class CropTool : ITool {
 }
 
 
+public class StraightenTool : ITool {
+
+  Photo photo;
+  float initialRotation;
+
+  public StraightenTool(Photo photo) {
+    this.photo = photo;
+    initialRotation = photo.Rotation;
+  }
+
+  public ToolStatus HandleInput(KeyboardState input, MouseState mouse, Transform transform, Game game, Photo photo, UiGeometry geometry) {
+    if (input.IsKeyPressed(Keys.Left)) {
+      photo.Rotation += 1;
+    }
+
+    if (input.IsKeyPressed(Keys.Right)) {
+      photo.Rotation -= 1;
+    }
+
+    if (input.IsKeyPressed(Keys.Enter)) {
+      return ToolStatus.Done;
+    }
+
+    if (input.IsKeyPressed(Keys.Escape)) {
+      photo.Rotation = initialRotation;
+      return ToolStatus.Canceled;
+    }
+
+    return ToolStatus.Active;
+  }
+
+  public void Draw(UiGeometry geometry, Game game) {
+  }
+
+  public string Status() {
+    return String.Format("[straighten] {0}", photo.Rotation);
+  }
+}
+
+
 public class UiGeometry {
   public static Vector2i MIN_WINDOW_SIZE = new(1024, 768);
 
@@ -678,6 +718,9 @@ public class Game : GameWindow {
       if (input.IsKeyPressed(Keys.C)) {
         activeTool = new CropTool(photos[photoIndex]);
       }
+      if (input.IsKeyPressed(Keys.S)) {
+        activeTool = new StraightenTool(photos[photoIndex]);
+      }
     }
 
     // Delegate input to the active tool.