Dan Coulter has written a very nice WordPress plugin that lets you easily add flickr photos and flickr galleries to a blog.
I use this over on a number of sites to link to various resources hosted on Flickr.
Unfortunately, the plugin as is does not work very well over HTTPS, since it references resources (javascript, css and flicker thumbnails) over HTTP. At the very least this can leak information about the page you are viewing, but in more modern browsers, the request itself is blocked and the page may not function correctly.
There was no obvious way to push patches upstream, so for now I’ve created my own fork of the code, and have stuck it on github.
Hopefully this’ll be useful to you!