Link field with Browse Server button
You can use the IMCE module.


  IMCE is an image/file uploader and browser that supports personal
  directories and quota.
  
  Features
  
  
  Basic file operations: upload, delete
  Image(jpg, png, gif) operations: resize, create thumbnails, preview
  Support for private file system
  Configurable limits for user roles: file size per upload, directory quota, file extensions, and image dimensions
  Personal or shared folders for users
  Permissions per directory
  Ftp-like directory navigation
  File sorting by name, size, dimensions, date
  Tabbed interface for file operations
  Keyboard shortcuts(up, down, insert(or enter), delete, home, end, ctrl+A, R(esize), T(humbnails), U(pload)).
  Built-in support for inline image/file insertion into textareas
  Multiple file selection(using ctrl or shift)
  Ajax file operations 
  Themable layout using tpl files