How to prevent users uploading images from their system? I have some image fields on my site.

My requirement is that the user should not be able to upload an image. Instead there will be a directory where I will place some images. And the user can only select an image from those images through image field.

Is it possible?
There are three major projects for handling media libraries in Drupal 7:


IMCE
Media
Scald


The most basic solution is IMCE. It is simply a file browser for files on your server. I.e. image files are just files on your server and Drupal isn't really aware of them and their meta-data.

The Media module uses in its ver. 2.0 File Entity module to manage media files, making it well aligned with the Drupal framework. It is a tried and tested solution for those who want something more sophisticated than IMCE.

Scald is a relatively new entry for media management. It comes with a very powerful media library sub-module and integrates seamlessly with the CKeditor WYSYWYG editor through drag and drop.  It has a bit steeper learning curve than the two others, but is IMHO well worth the effort.

Whether users are allowed to upload files (as opposed to pulling them from a library) are for all three projects handled by permissions settings.