[url removed, login to view] code shall work with a standard html img block. For example:
<img src="[url removed, login to view]">
[url removed, login to view] when an arbitrary flickr image url is redirected to the photo_unavailable image. For example, the image url used for item 1 above, will be redirected to: [url removed, login to view]
[url removed, login to view] code shall make a callback to a function that will provide a substitute URL for the unavailable url and then attempt to display the substitute image. For example, the following url will render correctly: [url removed, login to view]
[url removed, login to view] user shall not see the photo unavailable image, since the substitute image shall be rendered in its place
I've attached a test file named redirect.html and a file that displays the expected results named redirectExpectedResutls.html.
Any image that redirects to photo_unavailable shall be substituted with: http://farm4.static.flickr.com/3135/3064882017_fa7eb4bc64_z.jpg
Images that don't redirect shall be rendered as expected.
Thus the first two img directives shall display the substitute url instead, while the last img directive shall render the url identified with the src attribute.