??????? Bug如题目所描述。尝试过将按钮的image指向的变量del_icon设置为global全局变量，但是不成功，会提示如“
AttributeError: 'PhotoImage' object has no attribute '_PhotoImage__photo'
”的错误。代码1是导致bug的源头。
????????代码1：
#!/bin/env python3
from PIL import ImageTk
import tkinter as tk
...
self.del_button = tk.Button(self.frame, text='DEL', width=20, height=20)
self.del_button.config(image=ImageTk.PhotoImage(resize(os.getcwd() + '/delete.png', 0)))
self.del_button.bind('<Button-1>', self.delete_selected_image)
self.del_button.grid(row=0, column=0, sticky=tk.W)
????????结果删除按钮不显示image，按钮上显示空白:
??????? 尝试将del_button的image指向的变量设置为局部变量，即下面所展示的代码2。
????????代码2：
#!/bin/env python3
from PIL import ImageTk
import tkinter as tk
...
self.del_button = tk.Button(self.frame, text='DEL', width=20, height=20)
del_icon = ImageTk.PhotoImage(resize(os.getcwd()+'/delete.png', 0))
self.del_button.config(image=del_icon)
self.del_button.bind('<Button-1>', self.delete_selected_image)
self.del_button.grid(row=0, column=0, sticky=tk.W)
??????? 结果删除按钮的image显示正常：
???????? 笔记：
??????????????? 不明所以的bug。判断潜在原因是：GC的问题。image属性需要指向明确的内存地址。方法返回的临时变量地址调用后即被回收，导致image指向空地址。
??????? resize()的代码：
#!/bin/env python3
from PIL import Image
def resize(path):
image = Image.open(path)
raw_width, raw_height = image.size[0], image.size[1]
min_height = 20
min_width = int(raw_width * min_height / raw_height)
return image.resize((min_width, min_height))