Codrops has very nice scripts to present images with their title and alt. I have integrated these scripts into a Drupal 8 content type. All credits go to Codrops. The module depends on the Asset injector and the PHP Filter module.
You just need the machine names of the content type and image field that you want to present. Also choose a style. Make sure you have the correct machine names, otherwise you get an error, of course. These names can be found in the content type.
Codrops provides thirty styles. I have integrated them all with. Test them out or look at the preview at Codrops if you wish.
The script uses the title and alt (alternative text) of the images. Fill them in...
These are then displayed on hover. You can see some examples of 2 styles I used.