Detail of PHP directives that affects file uploading.

1. PHP File uploading post_max_size, upload_max_filesize & memory_limit

3. enctype=”multipart/form-data” means “Content-type of HTTP Request is multipart/form-data”

4. PHP Directives post_max_size upload_max_filesize upload_max_filesize PHP 5.2 File File header Part 1 Part 2 Part 3 decode decode HTTP Request HTTP Request Header Content-type: multipart/form-data HTTP Request Body Decoding needs tiny working buffer. The buffer is allocated within memory_limit .

7. If you want to read whole uploaded files in PHP, you'll consume huge memory. But it is another thing from file uploading. post_max_size > upload_max_filesize * (how many files) * 1.3 PHP 5.2

10. 17.13.4 Form content types