Nolan Chou

Sometimes we forgot change our file to a available name. So the plugin can help you auto change your upload file. 
I will add a filetype option of setting in next version. 
And a rename popup before the file upload if you change setting in future, default value is post_name.

wp_upload_rename

Change upload filename to random characters / random numbers / date / other by yourself.

Grégory Viguier

WordPress 3.5 removes the setting fields to change the media upload path and url. This plugin enables them again. Note that as long as your fields are not empty, you can disable this plugin.

Upload Url and Path Enabler

Get the media upload path and url setting fields back in WP 3.5+.

wp_upload_rename vs Upload Url and Path Enabler