Many photography lovers consider 500px's photo hosting service to be a Flickr 2.0 of sorts. The snail's pace with which Yahoo has brought new functionality to Flickr has led some users to abandon the once-beloved site in favor of alternatives like 500px, Zenfolio, and SmugMug — not to mention the vast number of consumers who are now uploading their pictures solely on Facebook. But 500px has evolved into a worthy foe to Yahoo's prized possession, and now the company has finally released an iPhone app. Previously an exclusive to Android and iPad owners (that version has also received a minor facelift) 500px for iOS is has been optimized for the iPhone 5 with a fluid design tailored to the smaller form factor.

One thing you won't be doing with the 500px app is uploading your own shots — bad news to the growing number of users that frequently use their phone as a primary shooter. The iOS app is more of a gallery showcase, and thankfully wading through the massive collection of user photos is made easy thanks to categories and a responsive search function. Unfortunately some limitations apply. You can't save the best shots to your camera roll, and we did experience some issues with zooming; there's no clear way to pan around an image once you do so.

Separately, 500px has brought an impressive social experience to the iPhone app by implementing profiles resembling your typical Instagram feed. All in all it's an impressive product that will likely leave 500px's customers very pleased and potentially draw in a new audience, so long as the inability to upload isn't a deal breaker.