When you use a blogging client from your computer/mobile-phone to upload photos to WordPress, WordPress resizes the 
image into smaller versions (e.g. thumbnail and medium) but the URLs of these resized images aren’t returned to 
the client so it can’t use them.
If clients are altered to support this plugin, when you include photos in an entry, the entry could automagically 
include the smaller images which link to the full size version when clicked on.
There is a patch to add the functionality in this plugin into the core of WordPress: 
https://core.trac.wordpress.org/ticket/6430 
but it missed the cut-off from WordPress 3.0 so it is unlikely to to be included for some time to come.

ImageURLReturner

When an XML-RPC Wordpress client uploads a photo, this plugin add the URLs for the resized images to the response so they can be used by the client in …

brainvireinfo

You can now disable XML-RPC to avoid Brute force attack for given IPs or can even enable access for some IPs. XML-RPC on WordPress is actually an API that gives developers who build mobile apps, desktop apps and other services, the ability to talk to a WordPress site. The XML-RPC API that WordPress provides gives developers, a way to write applications (for you) that can do many of the things that you can do when logged into WordPress via the web interface.
<h4>Features</h4>
Block XML-RPC by following way.
<ul>
<li>Disable pingback.ping, pingback.extensions.getPingbacks and Unset X-Pingback from HTTP headers, that will block bots to access specified method.</li>
<li>Disable/Block XML-RPC for all users.</li>
</ul>

Manage XML-RPC

Enable/Disable XML-RPC for all or based on IP list, also you can control pingback and Unset X-Pingback from HTTP headers.

ImageURLReturner vs Manage XML-RPC