added transcoding to mp4 in import to ensure web playback.

app/main.py

@@ -2,8 +2,8 @@
 
 from flask import Blueprint, render_template, flash, redirect, url_for, abort, send_from_directory, request, jsonify
 
-from sqlalchemy import desc, func, text, extract
-from sqlalchemy.orm import joinedload
+from sqlalchemy import desc, func, text, extract, and_
+from sqlalchemy.orm import joinedload, aliased
 from collections import OrderedDict
 from datetime import datetime
 
@@ -400,11 +400,15 @@ def tag_list():
       /tags?kind=series -> only series tags
       /tags?kind=rating -> only rating tags
     Shows a few preview images per tag.
+
+    Optimized to use 2 queries instead of N+1:
+    1. Get all tags with counts
+    2. Get preview images for all tags at once using window function
     """
     images_per_tag = 3
-    kind = request.args.get('kind')  # 'artist' | 'archive' | 'user' | 'character' | 'series' | 'rating' | None
+    kind = request.args.get('kind')
 
-    # Get tags with image counts
+    # Query 1: Get tags with image counts
     q = db.session.query(
         Tag,
         func.count(image_tags.c.image_id).label('img_count')
@@ -415,26 +419,55 @@ def tag_list():
 
     tags_with_counts = q.order_by(Tag.name.asc()).all()
 
-    tag_data = []
+    # Build tag_id list and initialize tag_data dict
+    tag_ids = [t.id for t, _ in tags_with_counts]
+    tag_map = {}
     for t, count in tags_with_counts:
-        imgs = (
-            ImageRecord.query
-            .join(ImageRecord.tags)
-            .filter(Tag.id == t.id)
-            .order_by(desc(func.coalesce(ImageRecord.taken_at, ImageRecord.imported_at)))
-            .limit(images_per_tag)
-            .all()
-        )
-        # Display label: for prefixed kinds use the part after ':', else full name
         label = t.name.split(":", 1)[1] if (":" in t.name) else t.name
-        tag_data.append({
+        tag_map[t.id] = {
             "id": t.id,
             "name": label,
             "tag": t.name,
-            "images": imgs,
+            "images": [],
             "kind": t.kind,
             "count": count
-        })
+        }
+
+    # Query 2: Get preview images for all tags at once using a subquery with row_number
+    # This fetches the top N images per tag in a single query
+    if tag_ids:
+        # Subquery to rank images within each tag
+        row_num = func.row_number().over(
+            partition_by=image_tags.c.tag_id,
+            order_by=desc(func.coalesce(ImageRecord.taken_at, ImageRecord.imported_at))
+        ).label('rn')
+
+        subq = (
+            db.session.query(
+                image_tags.c.tag_id,
+                ImageRecord.id.label('image_id'),
+                row_num
+            )
+            .join(ImageRecord, ImageRecord.id == image_tags.c.image_id)
+            .filter(image_tags.c.tag_id.in_(tag_ids))
+            .subquery()
+        )
+
+        # Get only the top N images per tag
+        preview_rows = (
+            db.session.query(subq.c.tag_id, ImageRecord)
+            .join(ImageRecord, ImageRecord.id == subq.c.image_id)
+            .filter(subq.c.rn <= images_per_tag)
+            .all()
+        )
+
+        # Group images by tag_id
+        for tag_id, img in preview_rows:
+            if tag_id in tag_map:
+                tag_map[tag_id]["images"].append(img)
+
+    # Convert to list maintaining original order
+    tag_data = [tag_map[t.id] for t, _ in tags_with_counts]
 
     return render_template('tags_list.html',
                            tag_data=tag_data,