lightbox helps

Photoset: Tumblr Lightbox

Tumblr are doing changes in their coding AKA theme trouble. Mainly their iframes which include tumblr controls, videos and the photoset lightbox. 

The lightbox changes: id (#) to class (.)

You need to change the following in css/style if you have styled lightboxes:

#tumblr_lightbox

.tmblr-lightbox

#vignette

.vignette

#tumblr_lightbox_caption

.lightbox-caption

#tumblr_lightbox_center_image, #tumblr_lightbox_left_image, #tumblr_lightbox_right_image

.lightbox-image

Edit: Before you change anything make sure your blog has been updated with the new codes - if not use the id’s.
There are a lot of tutorials on how you edit the lightbox, these tutorials still apply you just need to change the id’s to the new classes.