Alternative Text for pictures in the Slider

Hi, I don't know how to fill in the information (title, description, alt) for my pictures in the image-slider. Those informations are requested from Google regarding SEO. I know, how to fill in the information for pictures you upload in your topic. But for the pictures in a slider you need to set a picture as featured content and there you don't have the options: title, description, alternative text... How do I fill in those information for a picture in the slider?