Sometimes in facebook, real accounts too gets photo verification. Its very hard to select right person becouse of having high unknown friends.
There are few resones behind being blocked
Sanding a spam massages.
Nowadays facebook spam detactors became more advance. We the systam finds a spam, systam shows a CAPTCHA code to verify. If you do spam again and again then you will get blocked.
Sanding high friend requests.
A comon boy or girl will not sand high requests in small time. Ex : If you sand 100 friend requests in a hour then systam will surly take any action. There are two actions can be taken on then invalid activity
1. They will block sanding friend request permission.
2. They will block your account and show you photo verifications.
Making High stories.
It mean if you make high stories like updating you status hourly, sharing any on page's posts, liking every thing. This things show that the account is not a real account becouse, a real boy or girl is not act like a bot. Everyone cares about own image.
So here is the steps to secure you account from photo verification.
1. you have to login to your Facebook account .
2. go to settings and scroll down and just go to account setting now 3. join a network and just add your college full name/school name .
4.fill all the mandatory details on the form.
Now , after completing all the steps above carefully , Facebook will mark you as a trusted user and will never ask you for photo Verification.
And you will not get ban by Facebook anytime in future.