Update app.py

app.py

@@ -46,7 +46,7 @@ if res:
     st.caption('请查收您的排班表')    #用于写字幕
     st.image(f'timetable_{res}.png')      #用于显示图像
 
-    with open("timetable.png", "rb") as file:
+    with open(f"timetable_{res}.png", "rb") as file:
         btn = st.download_button(
              label="下载排班表",
              data=file,