Lightbox Image Captions

The thumbnail image has alt text and an overlay caption which can be styled with a transparent background. The caption can show on page load or, as in this example, show on hover or tap.
The thumbnail image can be styled with a border and/or a box shadow.
Clicking or tapping the thumbnail opens the large image in the lightbox. The lightbox image is responsive and has a caption and an optional border to provide seaparation from the overlay.
Maximum Width
The lightbox image is responsive up to the actual width of the image file. To control oversized or long skinny images, a maximum width can be set in pixels. This can be changed to a percentage width by checking a box and setting the percentage width using the slider.