diff --git a/croppa/main.py b/croppa/main.py
index 5f48c4b..6342929 100644
--- a/croppa/main.py
+++ b/croppa/main.py
@@ -119,12 +119,13 @@ class ProjectView:
         if size is None:
             size = self.THUMBNAIL_SIZE
         
-        # Use a cache key that includes the size
-        cache_key = (video_path, size)
-        if cache_key in self.thumbnails:
-            return self.thumbnails[cache_key]
+        # Cache the original thumbnail by video path only (not size)
+        if video_path in self.thumbnails:
+            original_thumbnail = self.thumbnails[video_path]
+            # Resize the cached thumbnail to the requested size
+            return cv2.resize(original_thumbnail, size)
         
-        # Generate thumbnail on demand
+        # Generate original thumbnail on demand (only once per video)
         try:
             cap = cv2.VideoCapture(str(video_path))
             if cap.isOpened():
@@ -134,10 +135,12 @@ class ProjectView:
                     cap.set(cv2.CAP_PROP_POS_FRAMES, middle_frame)
                     ret, frame = cap.read()
                     if ret:
-                        thumbnail = cv2.resize(frame, size)
-                        self.thumbnails[cache_key] = thumbnail
+                        # Store original thumbnail at original size
+                        original_thumbnail = cv2.resize(frame, self.THUMBNAIL_SIZE)
+                        self.thumbnails[video_path] = original_thumbnail
                         cap.release()
-                        return thumbnail
+                        # Return resized version
+                        return cv2.resize(original_thumbnail, size)
             cap.release()
         except Exception as e:
             print(f"Error generating thumbnail for {video_path.name}: {e}")