How to prevent android from auto-sync'ing gmail contacts and photos etc
To turn off syncing of everything to google, except mail then you can try the following steps:


Go to "Settings" on your phone -> "General" -> "Accounts" -> "Google" -> click your email address in the top. From here, you can uncheck checkboxes on everything you don't want to sync with Google.
Google+ also has its own syncing options -> Go to "Settings" on your phone -> "General" -> "Accounts" -> "Google" -> "Google+" -> "Auto backup". In the top, you can choose "Off" to turn off the backup of pictures and files to Google+.


I hope this helps.