Photobucket question

If i saved a photo on photobucket and used the medium preset and now I think it is too small...can I change the size to make it larger? When I go to edit it only offers me smaller sizes not larger.

Or do I have to go back and save from the original again.

I believe you have to resize from the orig..certain changes I know you cannot un-do if you overwrite the original. HTH, I'm not 100% but I frequently use the site and that has been my experience