file_copy in core/includes/
Copies a file to a new location and adds a file record to the database.
file_file_access in core/modules/file/file.module
Implements hook_file_access().
file_move in core/includes/
Moves a file to a new location and update the file's database entry.
file_save_data in core/includes/
Saves a file to the specified destination and creates a database entry.
template_preprocess_user_picture in core/modules/user/
Process variables for user-picture.tpl.php.
views_handler_field_user_picture::render in core/modules/user/views/
Render the field.