I don’t even post my top posts and pages widget as they already have traffic so I can’t see the value in promoting them. Instead I encourage traffic flow by featuring posts and pages that have good information in them but the readers have overlooked.
You would have to add the little thumbnails “by hand” yourself. There is not automatic way to do it. Easiest way is to use a draft post to arrange your thumbnails and make them link to the posts of your choice. Then copy/paste the code into a text widget.