How a user can upload his own picture?

[marla]

Hello everybody,

 

I want to create a shop when users can transform creative objects with their own illustrations.

So I want to install a simply "upload button" for allow them to upload their pictures. But the pictures should go on the back office (I prefer verify before...) and no directly on the front office.

This is an exemple:

http://en.lafraise.com/Contest/submit

Do you see "parcourir button" and "upload button"?

 

This what I want and I have no idea how to proceed...

Please Help Me ^^

 

Ps: sorry for my poor english..