That setPermalink sets some information that the Akismet system wants to collect/verify. It should normally point back to your blog. But since we're here not talking about a blog, but about a whole lot of different pictures, it's not quite obvious what to correctly fill in here... It may, at some point in time, prevent Akismet from catching all the spam if it doesn't point back to the exact URL for which the system is put to work, but I don't think that's the case now.
Akismet reads every message posted to your gallery against a database of spam messages that have been submitted and identified as spam by users. There may be some spam messages which are clearly spam, but haven't been identified as such by any Akismet user (yet). Those spam messages will get through. Don't expect Akismet to catch everything! If you want to implement and never look back, consider Captchas instead.
If you want to check whether your Akismet implementation works, you have to send a comment to your gallery which is clearly in the Akismet database. There're a few sample spam messages a few pages up in this thread, which have done the trick for me a few months back.
You may also look into your server logs or, better, webstats if you compile them for instance with Awstats. If your hits on db_input.php are considerably more frequent than ham AND spam arriving at your gallery, it's my understanding that Akismet is filtering something. Also, I've found that the spambots posting to my site hit directly on db_input.php, without doing some camouflage moves through the gallery before. Which means my Awstats counts them as Entry/Exit to the site. Normal legit users shouldn't enter the site at the comment input script, I would believe. So you can count those Entry/Exit hits, or hosts which don't leave any trace other than hits con db_input.php, as spambots, and see whether the number of those hits is considerably higher than the Spam arriving at your gallery. If it is --> take it as evidence that Akismet is performing.
Also a trace of the spammers in your webstats: Hosts which make as many hits as pageviews. I don't think there's any page which is worth just one hit in most of our sites, so you can assume that those one-hit-per-pageview visits are spambots. Again, to have an idea how much exposure to spambots you have, and to weigh it against the spam that's actually arriving.
The shame is that we don't have the full plugin promised by Pharaoweb so far. With that, we could submit our own spam samples to Akismet, and we could also see what's identified as spam by Akismet. We could be full Akismet users, in other words. But I'm not complaining! :-)