OK i did some tests:
preparation
I used three pages, one normal page (A) and two static pages (B and C) and inserted three gif-images (a,b,c) in page (A) and (B) and left Page (C) untouched.
Two of the images (a,b) where placed in the root media directory ("/uploads") and the third image (c) where placed in the directory "/uploads/sonstiges"
One question: Is it important for the test that all images have "<!-- s9ymdb:207 -->" because using the button for the media manager in the editor for static page (B) does not work.
execution
Now I used the mediamanager in the administration surface and moved image (a) one directory deeper from "/uploads" to "/uploads/sonstiges"
The results
The moved image (a) has a new correct url in normal page (A) and static page (B)
The url of the image (b) which is still in media root "/uploads" is mistakenly changend to "/uploads/sonstiges" in both pages (A and B) and therefore not visible anymore.
The url of the image (c) which was already in "/uploads/sonstiges" is still correct in the normal page (A)
but is changed to /"uploads/sonstiges/sonstiges" in the static page (B)!
In static page (C) which did not contain any of the images (a,b,c) but some other urls (a linked iframe) with content from "/uploads" and some images from "/uploads/sonstiges"
ALL of the urls are wrong now, because in all urls is inserted the subdir "../sonstiges/...".
OK, i am away to fix my pages now manually

I hope it helps you.