Are Featured Images SEO friendly?

My Q. is: are Featured Images SEO friendly? I do assign title, alt text and description to every image uploaded to site, however I am wondering if they are SEO friendly, because when I hover the mouse over a featured image on a single post, usually the the title of the image should pop up, none of these works in your template. Do search engines capture Featured Images? Thanks

If You look at source code, the images do have alt tag attached so they are SEO friendly .