It's actually even easier to link photos now, once you find the link. Flickr does most of the hard work for you.
1. On the image you want to display, click "Share This" -> "Grab the HTML/BB Code".
2. Select the BB Code
option and the size of the image you want to display.
3. Copy & paste the text provided; make sure you scroll down within the text box to get all of it.
The copied text will give the photo a title & photographer, linking back to the photo and user's page respectively. The image itself is also a link to the photo page.
As an example, here's the text provided:
[url=http://www.flickr.com/photos/adria_starbug/4778425839/]USS76_j12[/url] by [url=http://www.flickr.com/people/adria_starbug/]Adria Starbug[/url], on Flickr
(to remove the text below the image, remove everything after the first [ /url])
And this is what it looks like:
by Adria Starbug
, on Flickr
I hope this is easy enough to follow!