The Amble (pro) theme includes a recent posts widget to display the most recent posts with thumbnails. The thumbnails are automatically generated from the featured image you upload for the post(s).

screenshot showing the Amble theme recent posts widget
  1. Go to Appearance > Widgets
  2. Drag the Amble Recent Posts widget into the sidebar position you want to show it in.
  3. Enter the number of posts to display
  4. Click the Save button