I have more than 8 years of experience working in custom web applications development.
I read your requirement. I already developed so many similar kind of websites earlier.
As per your requirement, I found below main features you want in the website,
Front End
1. Login/Logout, Signup
2. User Photo Gallery where User can upload photos, view photos
3. User Blog where User can publish Articles with Hashtags
4. Search Articles with Hashtags
5. Latest Approved Articles will be displayed on Landing page
Administrator
1. Login/Logout
2. User Management ( Where All types of Users will be seen to Admin )
3. Photos of Users
4. Articles ( Here Admin can Approve/Deny any Article. )
I am proposing this website to be build with,
1. CakePHP / Codeingiter
2. Bootstrap based Admin Panel
3. MySQL
If above features are fixed then website should take approax. 128 hours. which includes,
1. Design + HTML - 24 hours
2. Development - 80 hours
3. QA + Bug Fixing + Deployment - 24 hours
I will be waiting for your replay. Lets start working together for a long lasting professional relationship.