Either PM me with your e-mail address, or if you go into the picture on Flickr at the top right hand corner you’ll see a plus sign in a spyglass-thing (between the words newer and older).
If you click on that plus sign you’ll now get the picture on a black background with, in the top right hand corner, the words “view all sizes” (or something like that).
If you click on that you will then get a version of the picture that should (depending on the resolution you have) be showing “large” (if it isn’t then click “large”)
You will then be able to right-click and save the picture.
Let me know if this works.