Local image input filter

Locks down image references to the host/domain of your site only, to prevent CSRF attacks, and avoid HTTPS mixed content errors.

In short: This input filter restricts image tags in HTML content submitted by users to your site.

Purpose

• Allow your users to use IMG HTML tags in posts
• while protecting against XSS attack vectors
• and using relative paths to allow the images to work on both http and https sites

Behavior

• This input filter finds all IMGs in a text, checks whether their src attribute is relative and points to an image under the Drupal root.
• Images satisfying that requirement are retained and left alone.
• All other images are removed.