The Media field form type was extended with two attributes and a new functionality:

component - The component can be defined from which the default image path is retrieved.

Example: component="com_example"

The default image path can then be defined in the manifest file of the extension. The name value to use is image_path.

mode - If the mode is strict and the user does not have upload rights, then a notice instead of the select button is loaded. This is useful to limit the access of the user only for a specific folder if he has upload rights (new com_media has to be modified to check for the used mode).

Example: mode="strict"

Placeholders for upload path

The path in the directory parameter can now contain the following placeholders:

{PLACEHOLDER}

username - The user name of the logged-in user.
userid - The ID of the logged-in user.
date() format characters - Default value transformation (see list here: http://php.net/manual/en/function.date.php)

Example: {username}, {userid}, {Y} or {Ymd}

Complete example:

<field name="image-upload" type="media" directory="{d}-{m}-{Y}/{username}-{userid}" component="com_example" mode="strict" />

In this example the upload path would consist of the date (day-month-year) and the username plus id (user-42). The default image path will be loaded from com_example (if available, else com_media) and the mode is set to strict which means that users without upload permission right will not be possible to load the modal window.

Small changed behavior: If the the selected folder does not exist, then this folder ist still used and not the root folder. This is necessary with the addtion of placeholders which create dynamic paths.