fix(upload): 모바일 QR 업로드 이미지 처리 수정

- PIL 이미지 처리 추가 (product-images API와 동일)
- 800x800 리사이즈
- 200x200 썸네일 생성
- RGBA->RGB 변환
- 1:1 중앙 크롭

backend/app.py

@@ -7682,21 +7682,62 @@ def api_upload_session_image(session_id):
         return jsonify({'success': False, 'error': '세션이 만료되었습니다'}), 404
     
     # 이미지 데이터 받기
+    import base64
+    from PIL import Image
+    from io import BytesIO
+    
     if 'image' not in request.files:
         # base64로 받은 경우
         data = request.get_json() or {}
-        image_base64 = data.get('image_base64')
-        if not image_base64:
+        image_data_raw = data.get('image_base64')
+        if not image_data_raw:
             return jsonify({'success': False, 'error': '이미지가 필요합니다'}), 400
     else:
         # 파일로 받은 경우
-        import base64
         file = request.files['image']
-        image_data = file.read()
-        image_base64 = base64.b64encode(image_data).decode('utf-8')
+        image_data_raw = base64.b64encode(file.read()).decode('utf-8')
     
-    # product_images.db에 저장
     barcode = session['barcode']
+    product_name = session.get('product_name', barcode)
+    
+    try:
+        # base64 디코딩 & PIL 이미지 처리
+        image_bytes = base64.b64decode(image_data_raw)
+        img = Image.open(BytesIO(image_bytes))
+        
+        # RGBA -> RGB 변환
+        if img.mode == 'RGBA':
+            bg = Image.new('RGB', img.size, (255, 255, 255))
+            bg.paste(img, mask=img.split()[3])
+            img = bg
+        elif img.mode != 'RGB':
+            img = img.convert('RGB')
+        
+        # 1:1 중앙 크롭
+        width, height = img.size
+        min_dim = min(width, height)
+        left = (width - min_dim) // 2
+        top = (height - min_dim) // 2
+        img = img.crop((left, top, left + min_dim, top + min_dim))
+        
+        # 800x800 리사이즈
+        img = img.resize((800, 800), Image.LANCZOS)
+        
+        # base64 변환 (원본)
+        buffer = BytesIO()
+        img.save(buffer, format='JPEG', quality=90)
+        image_base64 = base64.b64encode(buffer.getvalue()).decode('utf-8')
+        
+        # 썸네일 생성 (200x200)
+        thumb_img = img.resize((200, 200), Image.LANCZOS)
+        thumb_buffer = BytesIO()
+        thumb_img.save(thumb_buffer, format='JPEG', quality=85)
+        thumbnail_base64 = base64.b64encode(thumb_buffer.getvalue()).decode('utf-8')
+        
+    except Exception as e:
+        return jsonify({'success': False, 'error': f'이미지 처리 실패: {str(e)}'}), 400
+    
+    # SQLite 저장
     try:
         img_db_path = Path(__file__).parent / 'db' / 'product_images.db'
         conn = sqlite3.connect(str(img_db_path))
@@ -7706,26 +7747,24 @@ def api_upload_session_image(session_id):
         cursor.execute('SELECT id FROM product_images WHERE barcode = ?', (barcode,))
         existing = cursor.fetchone()
         
-        product_name = session.get('product_name', barcode)  # 세션에서 가져오거나 바코드 사용
-        
         if existing:
             cursor.execute('''
                 UPDATE product_images 
-                SET image_base64 = ?, updated_at = CURRENT_TIMESTAMP
+                SET image_base64 = ?, thumbnail_base64 = ?, status = 'manual', updated_at = datetime('now')
                 WHERE barcode = ?
-            ''', (image_base64, barcode))
+            ''', (image_base64, thumbnail_base64, barcode))
         else:
             cursor.execute('''
-                INSERT INTO product_images (barcode, product_name, image_base64, status, created_at)
-                VALUES (?, ?, ?, 'manual', CURRENT_TIMESTAMP)
-            ''', (barcode, product_name, image_base64))
+                INSERT INTO product_images (barcode, product_name, image_base64, thumbnail_base64, status)
+                VALUES (?, ?, ?, ?, 'manual')
+            ''', (barcode, product_name, image_base64, thumbnail_base64))
         
         conn.commit()
         conn.close()
         
         # 세션 상태 업데이트
         session['status'] = 'uploaded'
-        session['image_base64'] = image_base64
+        session['image_base64'] = thumbnail_base64  # 폴링용으로 썸네일 사용
         
         return jsonify({'success': True, 'message': '이미지가 저장되었습니다'})