Most file uploads can be restricted.
This option does not affect forms that use POST
but do not include any file upload.
This option can restrict uploads in various ways:
- -1 : never block or restrict a file upload
- 0 : always completely block file uploads
- n : limit only those file uploads larger than this
(setting is in kilobytes, for example 512 means 512KBytes,
and is the size of the file itself not including MIME encoding or headers)