I think I’ve blogged this problem before, but given how great it is to post Flickr photos to a blog (even those from others with credit automatically linked), I think I need to repeat this.    My problem after setting up a new blog was not to to this:

In WordPress dashboard under Settings > Writing > Remote Publishing be sure to check both Atom Publishing Protocol and XML-RPC

Which blogging services does Flickr support?

We currently support the following blogs:

• Atom Enabled Blogs
• Blogger *
• LiveJournal
• Manila
• Meta Weblog API Enabled Blogs
• Movable Type**
• Typepad
• Vox
• WordPress***

*Note: In 2007 Blogger moved to a Google ID based login procedure. If you have blog which was supported under the email login schema, you’ll need to delete the existing blog entry in your blog settings and generate a new one. Then you’ll be asked to confirm your Blogsettings on Blogger. Also, at this time, only one Google ID is supported for each Flickr account for Blogger. If you have more than one Blogger blog, they’ll all need to be associated with the same Google ID.

**Note: If you use a Movable Type v4 blog, you don’t use your normal password to log in. When you edit your user account on your blog host, there’s an option called Web Services Password, with an option to reveal it (it’s an MD5-type hash), and you should use that as the password for the configuration on Flickr, not your normal password.

***Note: If you use a WordPress self-hosted blog, in your WordPress dashboard under Settings > Writing > Remote Publishing be sure to check both Atom Publishing Protocol and XML-RPC. Then, in your settings on Flickr for that blog, enter your WordPress API Endpoint; for example: yourdomainame.com/xmlrpc.php