Blogo is a really simple and easy to use application that allows you to make blog posts from your desktop.
From their website:
Easily publish text, images, videos, slideshows and more.
With a simple, intuitive interface and support for Wordpress, Blogger, Typepad, Typo, Drupal, Joomla, and Expression Engine, Blogo is the best
way to maintain your blog and spread the word with Twitter, Ping.fm and other supported services.
As a test, I am publishing this from it to see how it works. It was able to upload pictures and it picked up the categories, but the selected category was not applied to the actual post, neither did the custom date.
It seems that the latest version of Flock works fine with Mango!
For some reason, categories are not properly sent. Since this is also a problem with Google Docs, I need to investigate what the issue is.
Update: It seems that as of version 0.2.4 the categories issue has been solved for Flock
Blogged with Flock
Mango blog supports publishing posts from a number of clients. This post has been published using Google Docs (formerly Writely)
Google docs also supports adding pictures to posts:
It does not seem to support setting this post's category, but it has text editing capabilities, such as bold, italics and font colors.