How to show thumbnail for image when edit the node Drupal 8
I resolved that issue.

Me steps:


go to image style and create new image style (/admin/config/media/image-styles).
go to View modes (/admin/structure/display-modes/view)
find Media section and create new view mode for media (/admin/structure/display-modes/view/add/media)
go to Media bundles (/admin/structure/media).
edit Image and go to Manage display (/admin/structure/media/manage/image/display)
click edit to your view



Now we can configure Paragraph content type or Content type