This is the alt attribute

This image was placed initially with Link To set to Media File. It uses a lightbox shortcode. In the visual editor, it shows code only, no GUI. The caption has wrong formatting. The lightbox does display the alt tag.

 

Bicyclist wearing big yellow pack fiddles with a snow covered bike.
This image was placed initially with Link To set to None and it got a caption shortcode. After placement, I changed Link To to Media File. In the visual editor, it displays as picture with GUI editor available. The caption has correct formatting. In the lightbox, neither the alt tag nor the title tag displays.

 

So how might we get a lightbox with GUI editor for a photo that does not have a caption? The following image was inserted without caption and with Link To set to none, then changed to Link To setting to Media File. No lightbox, which makes sense since there is no shortcode.

Rider leads pack horses up high with big view of mountains

Next, I’m trying the same approach, but with manual insertion of class=”themeblvd-lightbox mfp-image”. (See: https://docs.themeblvd.com/article/26-lightbox-integration) This does produce a clickable lightbox, but lacks the visual lightbox indicator on hover. The title attribute of the tag shows as a caption in the lightbox.

two women sitting with horse lying down