permissions - Restrict access to everything but some files - Ask Ubuntu

so want setup user account can open firefox (without internet connection, localhost php script can upload image php script (so var/www/html/ should writeable think)

also need able make photo webcam application , save desktop example.

explanation in short: user makes photo webcam, , open firefox upload http://www.coolphptools.com/color_extract#demo php script (which setup apache2 in var/www/) see colors photo contains. user has do.

but not want user access else. no settings, not delete (if possible) no looking around in other directories or files.

i have administrator account set password. other user shouldnt able else making picture webcam , running firefox , uploading image there script.

is @ possible?

this project real life gaming event. dont want idiot mess computer deleting wrong files or anything. there way this. , if not best solution make safe possible? thought ubuntu choice because can run php apache2 , think has lot of possibilities setting secure account. cannot find information it.