Background image set to cover & center. Change image for different one at diff media queries.
.hero {
background: black url(images/hero-1.jpg) center / cover;
}
@media (max-width: 1024px) {
.hero {
background: black url(images/hero-2.jpg) center / cover;
}
}
@media (max-width: 768px) {
.hero {
background: black url(images/hero-3.jpg) center / cover;
}
}