From top post.
Do you want to use the cover of the last book opened as a screensaver? Make sure you've installed the Python package first, then just drop a blank file named cover in the linkss folder. Restart your Kindle ([HOME] -> [MENU] > Settings -> [MENU] > Restart), and you're done .
Are you trying to use the book covers? that is the only reason you would need python (which is why I said it)