page used to change the join form?

I need to change the join form to have it required to put profile picture in. What page do I go to, to make this happen?

you can do this in the database   look in sys_profile_fields  look for ProfilePhoto and change the mandatory from 0 to 1   then clear the cache from the dolphin admin panel.... 

I found the ProfilePhoto section and changed mandatory to 1 but it hasn't changed in the join form.

clear your DB cache.