The present invention provides an improved security document having a “see-through” security feature that protects a window of the security document in which personalization information may be displayed, such as an image of the authorized document holder. The “see-through” security feature is provided by front and back side images, such as text (e.g. micro-text or encoded indicia), graphics or other image type, that may be laser marked onto the document substrate from a front side thereof through the window to a back side of the window. At least a part of the front image and at least a part of the back image are in front-to-back registration in window, the registration of the images being subject to verification by suitable inspection of the window. The front and back images may be partial images of a composite image when joined together at a juncture with the front-to-back registration of the partial images located at the juncture so that the images together have an appearance of the composite image in the window. Alternatively, at least a part of the first and second images may be identical with the front-to-back registration of the images located at least one of the identical parts so that the first and second images have an appearance in the window of a single image at those identical parts of the front-to-back registration.