Hi,
PHP scripts are limited by your php.ini in memory limit and in processing time.
Because of these limits, we avoid as much as possible to do intensive processing in order to avoid fatal errors and crashes generated by these limits.
Moving all the images of all the products at once is a process which could do that if we were to do it.
So when you change the folder in the HikaShop configuration, it's up to you to move the files from the old folder to the new one via FTP or your cpanel or the SSH of your server.
You don't have to edit each product. Just move the files as explained above.