I don't know if this has been fully rolled out yet (so yours may not have changed yet, or this may be old news to you) but yesterday my Facebook account started displaying photos differently.
Now when you click on a photo in an album it opens in an inset window rather than going to a new page.
This new window resizes dynamically to fit your browser window.
Basically if you're displaying images on Facebook and you want to guarantee they look decent you need to drop the resolution so it will definitely fit this window on everyone's monitor. Facebook's own 720 pixel on the long side size is too big for portrait orientation images on my 1280x1024 monitor.
They've also removed right click saving and added the "Download Photo" option to all images as far as I can see, so photo theft is now being actively advertised.
This affects personal profiles and fan pages.



