In a lot of applications, users need to be able to upload files. For example, most social networks allow users to upload pictures.
We will modify the web application to allow users to upload pictures when they are viewing details about a specific phone. After some time, other users will be able to browse a gallery of user-uploaded pictures for each of the phones.
To do that, we will use the file upload capabilities of PHP.
It is important to make sure that the uploaded file is of the proper kind and size.