在再次打开之前关闭Windows程序

Question

我的目标是打开图像一定时间，然后再显示另一个随机图像。

Windows将每个图像作为新实例打开，因此我想在打开新图像之前关闭旧图像。

自动执行此操作的绝对最简单的方法是什么。除了不关闭旧图像这一件事之外，简单的程序几乎可以按预期工作。

cont = True

#### Time Functions
def waits(): # basic wait
    time.sleep(s)
def waitm(): # basic wait
    time.sleep(s)
def waitl(): # basic wait
    time.sleep(s)
def wait(): # wait between notes
    time.sleep(wt)

g3 = Image.open(imd+"g3.png")
a3 = Image.open(imd+"a3.png")
b3 = Image.open(imd+"b3.png")
c4 = Image.open(imd+"c4.png")
d4 = Image.open(imd+"d4.png")
e4 = Image.open(imd+"e4.png")
f4s = Image.open(imd+"f4s.png")
g4 = Image.open(imd+"g4.png")

def randomNotes():
    GM_s_o = (g3, a3, b3, c4, d4, e4, f4s, g4) # G-major scale, open string # f
    r_note = random.choice(GM_s_o)

    r_note.show()
    waits()

def waitTime():
    global wt

    print("Choose wait time.")
    answer = input("s for short, m for medium, l for long.")

    if answer == "s":
        wt = 3
        return wt
    if answer == "m":
        wt = 6
        return wt
    if answer == "l":
        wt = 10
        return wt
    else:
        waitTime()

def program():
    global cont

    if cont == True:



        randomNotes()
        randomNotes()
        randomNotes()
        randomNotes()
        randomNotes()
        randomNotes()
        randomNotes()


        print("Would you like to continue?")
        answer = input("y for yes, n for no.")

        if answer == "y":
            cont = True
            program()

        if answer == "n":
            cont = False


    if cont == False:
        exit()

#### Actual

waitTime()
program()