You have to get the image URL (ending in .jpg), rather than the URL of the HTML page. Flickr generates BBCode that you can just copy-paste:
[url=http://www.flickr.com/photos/92369419@N03/8394670175/][img]http://farm9.staticflickr.com/8376/8394670175_05cc79b5cc.jpg[/img][/url]
[url=http://www.flickr.com/photos/92369419@N03/8394670175/]Starter Mania[/url] by [url=http://www.flickr.com/people/92369419@N03/]davidgzach[/url], on Flickr
Starter Mania by
davidgzach, on Flickr