Add fast layout update for image overlay

Introduce _apply_layout_fast to update the image overlay quickly on window resize using the cached QImage and FastTransformation. Called from the Resize event handler before the resize timer, it handles wallpaper mode (fast scale, center-crop to parent) and non-wallpaper mode (positioning by state.image_position and state.image_offset) to provide immediate visual feedback without running the heavier _apply_layout.

src/interface/dialogs/image.py

@@ -35,6 +35,7 @@ class Image(QObject):
     def eventFilter(self, obj, event):
         if obj == self.application and event.type() == QEvent.Type.Resize:
             if self._current_image_path:
+                self._apply_layout_fast()
                 self._resize_timer.start()
         return False
 
@@ -141,6 +142,41 @@ class Image(QObject):
 
         self._apply_layout()
 
+    def _apply_layout_fast(self):
+        if self._cached_qimage is None or not state.image_enabled:
+            return
+
+        parent = self.application
+        image = self._cached_qimage
+
+        if getattr(state, "image_as_wallpaper", False):
+            scaled = image.scaled(
+                parent.size(),
+                Qt.AspectRatioMode.KeepAspectRatioByExpanding,
+                Qt.TransformationMode.FastTransformation
+            )
+            cx = (scaled.width() - parent.width()) // 2
+            cy = (scaled.height() - parent.height()) // 2
+            cropped = scaled.copy(cx, cy, parent.width(), parent.height())
+            self.overlay_label.setPixmap(QPixmap.fromImage(cropped))
+            self.overlay_label.setGeometry(0, 0, parent.width(), parent.height())
+        else:
+            w = self.overlay_label.width()
+            h = self.overlay_label.height()
+            pos = state.image_position
+            off = int(state.image_offset)
+            if pos == "top-left":
+                x, y = off, off
+            elif pos == "top-right":
+                x, y = parent.width() - w - off, off
+            elif pos == "bottom-left":
+                x, y = off, parent.height() - h - off
+            elif pos == "center":
+                x, y = (parent.width() - w) // 2, (parent.height() - h) // 2
+            else:
+                x, y = parent.width() - w - off, parent.height() - h - off
+            self.overlay_label.move(x, y)
+
     def _apply_layout(self):
         if self._cached_qimage is None or not state.image_enabled:
             self.overlay_label.hide()