With Quick Featured Images Pro (QFIP), a plugin for WordPress, you can – among many other tasks – bulk set featured images for pages. Pages are a hierarchical post type in WordPress. A hierarchical post type let you define parent pages with child pages. That way you can set a hierarchy of pages.
In “Set, replace, remove”, the bulk edit section of Quick Featured Images Pro, you can set featured images to child pages of a selected parent page with the easy-to-use “Parent Page Filter”. Up till version 5.2 of QFIP this filter supported WordPress standard pages only.
Since version 5.2 of QFIP the “Parent Page Filter” gives you the posibility to bulk set featured images for child pages of any hierarchical custom post type. The custom post type is listed in this filter if it is a hierarchical type and supports featured images.