Flickr now gives you a litle 'Share This' button to click on which gives you HTML code to copy and paste.
Doesn't work on Safari on a Mac, and I can't find a way to adjust the size.
Also, it'd be nice if the photo title, username and license info were added under the photo. Is it that hard to think of these things?
A Certain Sense of Hopelessness by Thomas Hawk. CC BY-NC
And while I'm at it, could you put the HTML on the photos' 'All Sizes' page like it is for your own photos?
Here's my first shared photo: