Please see my comments to the question.
You can store the fixed 360 degrees panoramic image on the server side and cut out a segment of it to send in HTTP response, in response to HTTP request to imitate panoramic scrolling. On top of it, you can show all kinds of information. The library I know which certainly will do the operations you need (and a lot more) with acceptable performance is ImageMagic. This is how to use it with PHP:
http://php.net/manual/en/book.imagick.php[
^].
There are more which I'm not familiar with, but you should better try and compare:
http://www.php.net/manual/en/refs.utilspec.image.php[
^],
http://www.php.net/manual/en/book.cairo.php[
^],
http://www.php.net/manual/en/book.image.php[
^],
http://www.php.net/manual/en/book.gmagick.php[
^].
I saw some panoramic images shown in interactive rotation on some sites, you can try to find some read-to-use solution, but I would first think of making my own albeit made out of existing Web controls and image processing library, because you can better take into account all your requirements and design ideas. In all cases, eventually it's good to see what others did.
Good luck,
—SA