Display image title as caption in gallery

Hello,
i’ve been searching for a way to automatically display the image title as a caption because the images are from products and their titles are the codes for costumers to identify them.

Here is an example of what i’m looking for : http://mymjoyas.esy.es/anillos/

a friend told me i should search for a css answer but as i’m new to the computer world then i couldn’t find nothing .