Yep. I requested that URI and Digg responded with a 500 Internal
Server Error status.
An internal error can occur for a number of reasons. The details of
each internal error is logged. We continuously monitor the logs for
the most frequent kinds of errors, hunt down the root cause, and
apply a fix. That's a time-consuming task, and even the most
frequent errors represent rare, exceptional conditions, so I'm not in
a position to explain this one or say when it might be fixed.
Digg.com itself can be affected by this sort of error. Digg.com is
likely to serve a page that includes that image, and the image won't
show up. Interestingly, the image does show up on the permalink page
for that story:
http://digg.com/tech_news/Cisco_Predicts_Big_Growth_for_the_Internet_to_Continue
That's because it uses a different size that's not affected by the error:
http://digg.com/tech_news/Cisco_Predicts_Big_Growth_for_the_Internet_to_Continue/p.jpg
("p.jpg" stands for "permalink" size, which is 160 pixels on the
longest side, aspect ration preserved. The one that responds 500,
"t.jpg," stands for "thumbnail" size, which is 80x80 with a cropping
heuristic.)
A really careful API application might pre-fetch the thumbnail to
ensure Digg responds with a 200 OK status before using it. But
because it's an exceptional condition, an API application might
reasonably do what Digg does: Request the image and tolerate occasional errors.