Making a photo its full size

The Scale photo to 100% button on the Photo Tool InfoBar takes the currently selected photo and scales it to its full size on the page. So for example if the selected photo is scaled down to 500 pixels wide, but the original imported photo was 1000 pixels wide, the photo on the page will be scaled up to 1000 pixels wide. When the document zoom is 100%, that means that each pixel of the image is mapped to each screen pixel.