[HEADING=1]High-Res Kindle Covers Downloads[/HEADING]
As an added Bonus you can replace <ASIN>, with the books code in these URLs, and obtain the high Res source covers Amazon uses to create the public facing scaled covers, these are usually even higher Res than the ones in the eBook.
[CODE]http://z2-ec2.images-amazon.com/images/P/<ASIN>.01.MAIN._SCRM_.jpg
https://m.media-amazon.com/images/P/<ASIN>.01.MAIN._SCRM_.jpg[/CODE]This works about 99% of the Time.

I've used this successfully even with eBooks removed from Amazon over a decade ago.
For those [URL=https://www.goodreads.com/][B]Goodreads[/B][/URL] is where I find the <ASIN> code.
It's still conveniently listed on the old site, the new “Beta” one you need to use the Amazon link.
A “Page Not Found” result, still gives you the <ASIN>, but Covers don't get removed, just the eBooks.

A better more detailed method, can be found using this Guide.
[SPOILER="Thonny Python Scripts + Calibre Hi Res Kindle Covers Plugin + Uhuru N’Uru’s eBook AIcons"]
[QUOTE="cognos, post: 245939, member: 3312"]
I wrote a little [URL='https://www.python.org'][B]python[/B][/URL] script that I run in (minimized) [URL='https://thonny.org'][B]Thonny[/B][/URL] that prompts for an [URL='https://en.wikipedia.org/wiki/Amazon_Standard_Identification_Number'][B]ASIN[/B][/URL] and opens a new web-page tab containing the Hi-Res cover

[CODE]
# Imported Modules
from easygui import * # dialog boxes
import webbrowser
import sys

while 1:
    Cover_URL = "http://z2-ec2.images-amazon.com/images/P/ASIN.01.MAIN._SCRM_.jpg"

    ASIN = enterbox("Enter ASIN: ")

    if ASIN is None: # User canceled
        sys.exit(0)

    webbrowser.open_new_tab(Cover_URL.replace("ASIN", ASIN))[/CODE]
[/QUOTE]
Using Cognos' Taffy Script as a Base, I've adapted it for three options, a combo Portal A+B variant, that tries both URLs at once.

Portal A+B variant has one downside, in that it opens both images, in new tabs when they both exist, which is the usual case, so it can get annoying.
[SPOILER="Python Scripts For Thonny"]
ASIN_Portal_A+B.py

[CODE=python]# Imported Modules

from easygui import * # dialog boxes

import webbrowser

import sys


while 1:

Portal_A = "http://z2-ec2.images-amazon.com/images/P/ASIN.01.MAIN._SCRM_.jpg"

Portal_B = "https://m.media-amazon.com/images/P/ASIN.01.MAIN._SCRM_.jpg"


ASIN = enterbox("Enter ASIN: Portal A+B Number")


if ASIN is None: # User canceled

sys.exit(0)


webbrowser.open_new_tab(Portal_A.replace("ASIN", ASIN))

webbrowser.open_new_tab(Portal_B.replace("ASIN", ASIN))[/CODE]
As an alternative, I've made two separated versions that, clearly indicate which portal is used.

[B]ASIN_Portal_A.py[/B]
[CODE=python]# Imported Modules

from easygui import * # dialog boxes

import webbrowser

import sys


while 1:

    Portal_A = "http://z2-ec2.images-amazon.com/images/P/ASIN.01.MAIN._SCRM_.jpg"


    ASIN = enterbox("Enter ASIN: Portal A Number")


    if ASIN is None: # User canceled

        sys.exit(0)


    webbrowser.open_new_tab(Portal_A.replace("ASIN", ASIN))[/CODE]
[B]ASIN_Portal_B.py[/B]
[CODE=python]# Imported Modules

from easygui import * # dialog boxes

import webbrowser

import sys


while 1:

    Portal_B = "https://m.media-amazon.com/images/P/ASIN.01.MAIN._SCRM_.jpg"


    ASIN = enterbox("Enter ASIN: Portal B Number")


    if ASIN is None: # User canceled

        sys.exit(0)


    webbrowser.open_new_tab(Portal_B.replace("ASIN", ASIN))[/CODE]
[/SPOILER]
Also I've edited the Calibre Plugin to search this new Portal B URL, I'll just show the relevant sources section here, and it's just the last line shown, that I've changed, otherwise the rest of the Plugin is unchanged.
[CODE=python]    sources = frozenset([

        'http://z2-ec2.images-amazon.com/images/P/{0}.01.MAIN._SCRM_.jpg',

        'https://m.media-amazon.com/images/P/{0}.01.MAIN._SCRM_.jpg',[/CODE]
You can also use the manual option as always.

The Thonny link is in Cognos post, it is required, so I've added link again here
[URL='https://thonny.org/'][B]Thonny, Python IDE for beginners[/B][/URL]
Using the Archives
[B]Thonny Python Scripts.7Z.001[/B]

This contains three files, and can be extracted anywhere, but I recommend your default Thonny User Scripts Folder.
If you extract the archive to your “AppData/Local” folder it will create the “Thonny/Scripts” folders in the extraction process, and you can then use the Environment Variable “[B]%LocalAppData%[/B]” to create Desktop Shortcuts, using these path names to the files.
[B]%LocalAppData%\Thonny\Scripts\ASIN_Portal_A.py
%LocalAppData%\Thonny\Scripts\ASIN_Portal_B.py
%LocalAppData%\Thonny\Scripts\ASIN_Portal_A+B.py[/B]

To “Run current script” in Thonny, press F5, or select the Right Pointing Green Triangle option from the toolbar, or from the run menu.
[B]Calibre Hi Res Kindle Covers Plugin [Zip].7z.001[/B]

This archive contains the Zip archive, that Calibre needs to import a plugin, so don't extract the contents of;
[B]Kindle.Hi-Res.Covers.v0.5.0-Updated.Portal.B.zip[/B]
[HEADING=2]Now Run Calibre, And Follow This Step By Step Guide[/HEADING]
[LIST=1]
[*]Click on [B]Preferences[/B] Tab (Top Left Corner), go to step 2, [B]OR[/B] use [B]Ctrl + P[/B] keyboard shortcut, and go straight to step 3.
[*]Click first choice [B]Change Calibre Behavior.[/B]
[*]In Preferences Window, select [B]Plug-ins[/B] Button (Bottom Left Corner).
[*]In Plug-ins window, select Load plug-in from file (Bottom Right Corner).
[*]Navigate to where you extracted the DeDRM Tools, and select the [B]DeDRM_plugin.zip[/B], then click open button.
[*]Follow the on screen instructions to install, then shut Calibre down, and restart to make sure plugin is used.
[/LIST]
Navigate to where you extracted the “Kindle.Hi-Res.Covers.v0.5.0-Updated.Portal.B.zip”, and install the plugin.[/SPOILER]