Lightbox is a whole new way to interact with photos. When clicked, images now expand into a shiny new overlay that displays them at their full size for optimal viewing.
Once an image is opened in the lightbox view, any other images from the same post will now appear as thumbnails along the bottom, which can be easily browsed by clicking the arrow keys on the left or right side of the lightbox.
If you’ve custom-coded your image HTML so that images function as hyperlinks, then the lightbox view will not display and your original image hyperlink will work as expected.
For some reasons, if you’d like to disable Lightbox on your blog, log in to Blogger and select “No” next to Lightbox in the Settings | Posts and Comments section (new interface) or the Settings | Formatting section (old interface).