Aaron Wormus has a quick note on his site about one of the up and coming web services availible out there - flickr.

(Today) an error message that arrived in my inbox, I was rewarded to find that Flickr runs PHP and smarty. The system still has a way to go before it's ready for prime time, there are some annoying bugs still floating around but then again it is still marked as beta.

Basically, this new image hosting services gains some of it's power from the fact that it runs PHP. All the way from the display of the images to the comments you can add to the photos themselves - flickr is definitely an up-and-comer in the image hosting world.