FreeCommander

Activating the main menu item "View → Thumbnails" or the shortcut "Ctrl+I" opens the view type "Thumbnails" and shows the items of the active folder in the active panel as small images:

The icon preceding this menu item changes from to .

The settings of this view type can be defined under the menu item "Tools → Settings → View → Thumbnails". This picture preview also works within archive files.

Activating the shortcut "Ctrl+I", when the view type "Thumbnails" is active, activates the previously active view type.