If you would like to show it in a new window, you could use Tkinter + PIL library, like so:

import tkinter as tk
from PIL import ImageTk, Image

def show_imge(path):
    image_window = tk.Tk()
    img = ImageTk.PhotoImage(Image.open(path))
    panel = tk.Label(image_window, image=img)
    panel.pack(side="bottom", fill="both", expand="yes")
    image_window.mainloop()

This is a modified example that can be found all over the web.

You can also using the Python module Ipython, which in addition to displaying an image in the Spyder console can embed images in Jupyter notebook. In Spyder, the image will be displayed in full size, not scaled to fit the console.

from IPython.display import Image, display
display(Image(filename="mypic.png"))

If you want to open the image in your native image viewer, try os.startfile:

import os

os.startfile('file')

Or you could set the image as the background using a GUI library and then show it when you want to. But this way uses a lot more code and might impact the time your script takes to run. But it does allow you to customize the ui. Here's an example using wxpython:

import wx
 
########################################################################
class MainPanel(wx.Panel):
    """"""
 
    #----------------------------------------------------------------------
    def __init__(self, parent):
        """Constructor"""
        wx.Panel.__init__(self, parent=parent)
        self.SetBackgroundStyle(wx.BG_STYLE_PAINT) # Was wx.BG_STYLE_CUSTOM)
        self.frame = parent
 
        sizer = wx.BoxSizer(wx.VERTICAL)
        hSizer = wx.BoxSizer(wx.HORIZONTAL)
 
        for num in range(4):
            label = "Button %s" % num
            btn = wx.Button(self, label=label)
            sizer.Add(btn, 0, wx.ALL, 5)
        hSizer.Add((1,1), 1, wx.EXPAND)
        hSizer.Add(sizer, 0, wx.TOP, 100)
        hSizer.Add((1,1), 0, wx.ALL, 75)
        self.SetSizer(hSizer)
        self.Bind(wx.EVT_ERASE_BACKGROUND, self.OnEraseBackground)
 
    #----------------------------------------------------------------------
    def OnEraseBackground(self, evt):
        """
        Add a picture to the background
        """
        # yanked from ColourDB.py
        dc = evt.GetDC()
 
        if not dc:
            dc = wx.ClientDC(self)
            rect = self.GetUpdateRegion().GetBox()
            dc.SetClippingRect(rect)
        dc.Clear()
        bmp = wx.Bitmap("file")
        dc.DrawBitmap(bmp, 0, 0)
 
 
########################################################################
class MainFrame(wx.Frame):
    """"""
 
    #----------------------------------------------------------------------
    def __init__(self):
        """Constructor"""
        wx.Frame.__init__(self, None, size=(600,450))
        panel = MainPanel(self)        
        self.Center()
 
########################################################################
class Main(wx.App):
    """"""
 
    #----------------------------------------------------------------------
    def __init__(self, redirect=False, filename=None):
        """Constructor"""
        wx.App.__init__(self, redirect, filename)
        dlg = MainFrame()
        dlg.Show()
 
#----------------------------------------------------------------------
if __name__ == "__main__":
    app = Main()
    app.MainLoop()

(source code from how to put a image as a background in wxpython)

You can even show the image in your terminal using timg:

import timg

obj = timg.Renderer()                                                                                               
obj.load_image_from_file("file")
obj.render(timg.SixelMethod)

(PyPI: https://pypi.org/project/timg)

You can use the following code:

import matplotlib.pyplot as plt
import matplotlib.image as mpimg
%matplotlib inline
img = mpimg.imread('FILEPATH/FILENAME.jpg')
imgplot = plt.imshow(img)
plt.axis('off')
plt.show()

Displaying images in console using Python

For this you will need a library called ascii_magic

Installation : pip install ascii_magic

Sample Code :

import ascii_magic

img = ascii_magic.from_image_file("Image.png")
result = ascii_magic.to_terminal(img)

Reference : Ascii_Magic

2022:

import os

os.open("filename.png")

It will open the filename.png in a window using default image viewer.