Falcon, if you want your picture in Flickr to show up in your post, left click on the picture to make it appear in a larger black rectangle. At the bottom right corner of that rectangle is a "Share" icon - it looks like a curving arrow pointing to the upper right. Click on that icon to display the share box. At the top of the share box click on the BBCode. Copy and paste the BBC into your post. (Before copying the code you can use the drop down box below the code to select the size you want the picture to appear as in your post. The largest of the "medium" options usually works well.)
Note: Pasting the entire BBCode will add some text before and/or after your posted picture. If you want to eliminate that text, delete those parts of the BBCode that appear before the after the IMG code (i.e. before
before clicking on the Submit button for your post.