PHPでFC2ブログに投稿(1)に続いて、画像付きで投稿したいと思います。
投稿が失敗したら、PEARをチェックしてください。
http://pear.php.net/manual/en/installation.checking.php

Movable Type で使える XML-RPC API

http://www.na.rim.or.jp/~tsupo/program/blogTool/mt_xmlRpc.html

MSのMetaWeblogAPI metaWeblog.newPost Method説明があります。

public string metaWeblog.newPost(
string blogid,
string username,
string password,
struct content,
bool publish);

インターフェースのパラメータ紹介は:

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Parameters
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<em>blogid [in]</em>
This should be the string MyBlog, which indicates that the post is being created in the user’s blog.
<em>username [in]</em>
The name of the user’s space.
<em>password [in]</em>
The user’s secret word.
<em>content [in]</em>
A  struct representing the content to update. The title, description,  dateCreated, and categories fields are supported. All other elements are  ignored. If multiple categories are specified, each category is added  to the category list until the maximum is reached, and all remaining  categories are ignored. An error is returned if no title is specified.  If no description or categories are provided, the post has no body or  category, respectively.
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struct {
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    string title;
    string description;
    dateTime.iso8601 dateCreated;
    string[] categories;
}
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<em>publish [in]</em>

If false, this is a draft post.
ほかに使えるメソッドについては以下のリファレンス トピックがあります。