Script needs to have a few of the photobucket functions like:
Similar sign up form
Gallery (example: xmlphotoalbum useable with users images)
Slideshow (example: useing one of the free ones around the web like the xmlphotoalbum idea for the gallery)
2 options for sign up "free" and "paid" with the paid being linked to paypal.
I know there are plenty of free scripts or similar ones for small prices around the web.
If you have a way to work in the above features to say [url removed, login to view] (imspro script), that would work also as long as it is a way to link the users to the above mentioned gallery..etc..