Web monitor if new images on a logged in page

Hello so i'm really not sure how to write this in python and a lot of the free page monitors don't do what I want it to do...

I need a way to monitor a webpage and see if there are any new images on the page and the webpage that I'm monitoring is through a login portal so I have to be logged in to be monitoring it

Anyone can give me an idea how to do this?

Thanks