Check "files" folder into Drupal From http://getlevelten.com/blog/mark-carver/dont-sync-drupal-files-local-environments-redirect-them-instead

new_gist_file_0

### Apache Rewrite  
# Request resides in your 'sites/default/files' folder.  
RewriteCond %{REQUEST_URI} ^/sites/default/files/(.*)$  
# File doesn't exist.  
RewriteCond %{REQUEST_FILENAME} !-f  
# Directory doesn't exist.  
RewriteCond %{REQUEST_FILENAME} !-d  
# Redirect request to your development or production server.  
RewriteRule ^/sites/default/files/(.*)$ 
http://dev.example.com/sites/default/files/$1 [L] 
### nginx Rewrite  
## Try local files first, otherwise redirect to a development server.  
location ^~ /sites/default/files {    
    try_files $uri @dev_redirect;  
    }  
## Development Server Redirect    
location @dev_redirect {    
    rewrite ^ http://dev.example.com$request_uri? permanent;  
    }