Featured post slider image size

Hi @Sakin I want to make my images on the featured post slider occupy the all size, i tried adding some function to my child´s theme function file and when i put a 16:9 aspect ratio image works nice, but when i put another aspect ratio image it makes smaller and leaves an empty zone, how can i make those images fill the empty zone, even i they are scaled and look stretched. You can have a look at mi site slider to look what i mean. My site URL Lots of thanks and best wishes