Can I use PHPture to rate images or make other modifications?
No, PHPture is designed as a viewing application for several very good reasons. Making modifications would require the library to be writable for other users as well, which could potentionally be a big security risk. Also, because Apple Aperture is designed for a single user it would introduce a number of concurrency issues when more than one person is making modifications to the library at the same time. Furthermore, it would require even more in-depth knowledge of the file-format because some changes could make it unable for Apple Aperture to use the library.