WordPress uploads and their permission on Windows Server

Experience: 

After default installation of WordPress on Windows Server, the administrator is usually confronted by an error which happens after the user is uploading an image:

This is caused by insufficient rights of the file.

Cause: 

Reason for this behavior is some PHP process, where the upload is first stored in c:\Windows\Temp and afterwards the file is moved to the target ‚wp-content‘ folder. By movement, the file privileges are not updated.

Mitigation:

To fix the issue, the upload folder needs to be changed to a folder, where IIS_IUSRS has read and write-access to the contained files.

This can be done by change the PHP.ini variable (http://php.net/manual/de/ini.core.php#ini.upload-tmp-dir) and setting the file privileges:

; Temporary directory for HTTP uploaded files (will use system default if not
; specified).
; http://php.net/upload-tmp-dir
upload_tmp_dir = C:\inetpub\temp\PHP

See also: https://stackoverflow.com/questions/23851821/setting-file-permissions-in-windows-with-php