Make sure all TARGET Media is attached to a Page (not a Timeline Event)
Wordpress calculates the Default URI / Original URL* as WhatEverItIsAttachedTo(IfItIsAttached)/NativeSlug (It is not saved, instead calculated)
The NativeSlug is stored in the wp_posts.post_name Table.Column, and can be easily modified with a SQL query
"Tag" the desired media (WhatEver1) to change with a custom date (1999-09-13, AKA September 13, 1999) using the Bulk Edit feature of Admin Columns
Use a SQL Query to add / prepend the new custom path (example: recent-history/images/, no leading /, but add the trailing)
Change date back to original or current
Then go to the next desired media and tag it (WhatEver2, 3, etc.) and repeat the above steps (3 lines)
...and after all SQL Modifications; Permalink Manager, Tools, Regenerate / Reset, Mode: Use Original (Default) URLs as custom permalinks
OR, go to debug tab (far right) and wipe all data.
Optional (Not recommended as it can be done via SQL): Permalink Manager, Tools, Regenerate / Reset, Mode: Regenerate Native Slug
*NOTE: Permalink Manager exchanges the use of "Current URI" with "Custom Permalink" in the Regenerate/Reset Tool
...and "Default URI" with "Original URLs" too.
Permalinks Manager: Regenerate custom permalinks and Use original URLs as custom permalinks does the same thing
(The Default URI is copied to the Current / Custom URI)
recent-history11/attachment11/salton-sea-stuck-boat-high-res-no-rv-not-as-vivid11
recent-history/attachment/salton-sea-stuck-boat-high-res-no-rv-not-as-vivid22
recent-history11/attachment11/salton-sea-stuck-boat-high-res-no-rv-not-as-vivid11
recent-history/attachment/salton-sea-stuck-boat-high-res-no-rv-not-as-vivid22