I guess the first question is what application set these odd attributes.
Did you try another extraction program, for example TheUnarchiver (free), Archiver (not free) or Express ZIP (seems free).
I just did a test myself by creating an IMG and have ApplePi-Baker compress it with 7Zip.
-rw-r--r--@ 1 root staff 58397496 Aug 17 11:21 TestImage.7z
I decompressed it "Archive Utility":
--w--wx-wT 1 hans staff 138412032 Aug 17 11:23 disk.img
Decompressed with "The Unarchiver":
-rw---x--T@ 1 hans staff 138412032 Aug 17 11:25 disk.img
Decompressed with "Entropy" (I suspect this application is no longer being developed)
--w---x--- 1 hans staff 138412032 Aug 17 11:26 disk.img
With "Forklift" (very nice and affordable File manager)
-rw---x--T 1 hans staff 138412032 Aug 17 11:28 disk.img
With "Path Finder"(powerful but expensive File manager)
--w--wx-wT 1 hans staff 138412032 Aug 17 11:29 disk.img
As you can see: the attributes are set all over the place. Weird.
Looks like 7Zip (like RAR and some other formats) may not be storing file premissions. But the used permission are just weird/idiotic indeed. They make no sense.
Note that APB should work just fine accessing the original 7zip file.
Very interesting find though ... 🤔
It would be an interesting test to compress the IMG again to 7Zip, and see what APB makes of it ..?
Also note: I have found that 7Zip is not the best format to compress images (especially when it comes down to backup and restore speed).