Expose image options on XML-RPC

[koke]

To pick good defaults when inserting images from the mobile apps, it'd be nice to have the following options exposed:

• image_default_link_type
• image_default_size
• image_default_align

This looks fine to me, just one question. What are the legitimate values for these options? My copy of WP -trunk has empty values for all three.

Defaults look like this to me:

mysql> select * from wp_options where option_name LIKE 'image%';
+-----------+---------+-------------------------+--------------+----------+
| option_id | blog_id | option_name             | option_value | autoload |
+-----------+---------+-------------------------+--------------+----------+
|        76 |       0 | image_default_align     |              | yes      | 
|        74 |       0 | image_default_link_type | file         | yes      | 
|        75 |       0 | image_default_size      |              | yes      | 
+-----------+---------+-------------------------+--------------+----------+

For image_default_size, trunk/wp-admin/includes/media.php#L730​:

// if $check is not enabled, default to the first available size that's bigger than a thumbnail

For image_default_align, defaults to 'none' in trunk/wp-admin/includes/media.php#L682​

Looks fine to me.

Patch looks good to me.

In [19884]:

Expose image_default_link_type, image_default_size, and image_default_align
options via XML-RPC

Props koke
Fixes #18126

Related: #20228