感谢Stovfl's comment我可以使用：

self.itemconfig(items[idx],image=image)

更改图像尺寸。不幸的是，缩放在tkinter中起作用的方式：

# rescale all objects with the "all" tag
self.scale("all",wscale,hscale)

图像没有完全填充边框，缺少一两个像素。因此我必须根据原始画布的宽度和高度生成自己的缩放因子：

# images use ratio of original width/height to new width/height
wiscale = float(event.width)/self.startw
hiscale = float(event.height)/self.starth

最后，为了防止垃圾收集器删除我将其重新分配到列表中的调整大小的图像，

resized[idx]=image  # stop garbage collector from removing image

TL; DR

如果您想在自己的项目中使用它，这里是完整的Python脚本：

#!/usr/bin/env python
# -*- coding: utf-8 -*-

try:
    from Tkinter import *
except ImportError:
    from tkinter import *

from PIL import Image,ImageTk

root = Tk()

images = []     # to hold the newly created image
resized = []    # Resized images
fills = []      # associated list of fill attributes
items = []      # associated list of canvass item tags / ids

# a subclass of Canvas for dealing with resizing of windows
class ResizingCanvas(Canvas):
    def __init__(self,parent,**kwargs):
        Canvas.__init__(self,**kwargs)

        self.bind("<Configure>",self.on_resize)
        self.height = self.winfo_reqheight()
        self.width = self.winfo_reqwidth()
        self.startw = self.width
        self.starth = self.height

    def on_resize(self,event):
        # determine the ratio of previous width/height to new width/height
        wscale = float(event.width)/self.width
        hscale = float(event.height)/self.height
        # Save new values as old values
        self.width = event.width
        self.height = event.height
        # images use ratio of original width/height to new width/height
        wiscale = float(event.width)/self.startw
        hiscale = float(event.height)/self.starth

        # resize images
        for idx,image in enumerate(images):
            fill=fills[idx]
            neww=int(image.width()*wiscale)
            newh=int(image.height()*hiscale)
            image = Image.new('RGBA',(neww,newh),fill)
            image = ImageTk.PhotoImage(image)
            self.itemconfig(items[idx],image=image)
            resized[idx]=image  # stop garbage collector from removing image

        # resize the canvas 
        self.config(width=self.width,height=self.height)
        # rescale all objects with the "all" tag
        self.scale("all",hscale)

def create_rectangle(x1,y1,x2,y2,**kwargs):
    if 'alpha' in kwargs:
        alpha = int(kwargs.pop('alpha') * 255)
        fill = kwargs.pop('fill')
        fill = root.winfo_rgb(fill) + (alpha,)
        fills.append(fill)
        image = Image.new('RGBA',(x2-x1,y2-y1),fill)
        images.append(ImageTk.PhotoImage(image))
        item=mycanvas.create_image(x1,image=images[-1],anchor='nw')
        items.append(item)
    mycanvas.create_rectangle(x1,**kwargs)

root.title('alpha1.py')

myframe = Frame(root)
myframe.pack(fill=BOTH,expand=YES)
WinWid=1490; WinHgt=860
mycanvas = ResizingCanvas(myframe,width=WinWid,height=WinHgt,\
                          highlightthickness=0)
mycanvas.pack(fill=BOTH,expand=YES)

create_rectangle(100,100,600,fill='blue')
create_rectangle(300,300,950,700,fill='green',alpha=.5)
create_rectangle(200,500,850,820,fill='#800000',alpha=.6)
mycanvas.addtag_all("all")
for image in images:
    resized.append(image)

root.mainloop()