I am developing an android app, search for real estate agents profile that contains basic info and picture. What database should i use Firebase or Mysql with php ? Please specify the best design approach
On the server? Definitely MySQL (now called MariaDB - Oracle owns the name MySQL).
The best approach is to not plan on storing pictures in the database. Store the pictures on the hard drive (or SSD) and store a link to them in the database.
Other than that, since we don't know what the site will be doing, you're on your own, unless you want to ask for specifics here.