If you have a Facebook application that queries the photo FQL table or uses photo.get, be sure to update your styling to accommodate these new sizes.
It's not just photo uploads that are changing in size; Facebook is also changing the size of profile pictures. In the next few weeks profile pictures will move to 180x540 pixels, this is down from 200x600. Yeah, that's right, profile pictures will now be smaller. Again, developers, adjust your applications accordingly.
One of the biggest complaints that users of Facebook have with the network is the limit on picture size. As one of the largest photo-sharing sites on the web, the limits are indeed kind of surprising. Still, it's nice to see an increase in pixel space, even if the increase isn't earth-shattering.