It seems the option to post BBcode directly copied from flickr share options has been removed.
I've tried in vain to post pictures using [img] and [url] tags.
So I have made a greasemonkey script that gives an extra option to flickr's share options: Grab the RSPB HTML.
To use it you have to click the HTML button in the rich editor when making a post on here and copy/paste the code into your post in the place you want the picture to show, then click update.
So when you are typing your post and get to the part you want the image to be, click HTML then click AFTER all the code and paste the code you copied from flickr, then click update.
A pain I know, but if you like to link your photo to flickr to offer larger versions to view this seems to be the easiest way I can think of.
I've tried the script on firefox and chrome (using tampermonkey) adn it seems to work well.
As I can't upload files here I've uploaded it to my web site http://www.rcwb.co.uk/flickr_RSPB.zip
Brian.
My Flickr
My own humble photo site
You know doggie, I feel a bit of an idiot now, I forgot all about the html code on flickr as I've always only used the BBcode