I made an app and put that on Playstore. Is there a way I can change the screenshots of the app? Or if it is not possible will the update version remove the previous version and screenshots?
You can change the screenshots if you go to the Google Developer Console.
You select your app from the list, then go to store presence and select store listing from the menu on the left and there will be a graphic assets section on the page. You can add them there.