Прошу прощения выложил промежуточный css. Правильный:
body{
background: #ccc;
margin: 0;
padding: 0;
width: 100%;
height: 100%;
overflow: auto;
display:flex;
flex-direction: column;
justify-content: center;
align-items: stretch;
}
.header{
margin: 0;
padding: 0;
height: 51px;
}

#slider{
margin: 0;
padding: 0;
width: auto;
height: auto;
display: block;
-webkit-box-shadow: 0px 0px 10px rgba(0,0,0,1);
-moz-box-shadow: 0px 0px 10px rgba(0,0,0,1);
box-shadow: 0px 0px 10px rgba(0,0,0,1);

}
#container{
margin: 0;
padding: 0;
width: auto;
height: auto;
background: #ccc;

display: block;
overflow: auto;
}

.back{
padding: 24% 1%;

float: left;
display: block;
z-index: 99;
position: relative;
}
.next{
padding: 24% 1%;
float: right;
display: block;
z-index: 99;
position: relative;
}
.images{
margin: 0;
padding: 0;
width: 100%;
height: 100%;
display: block;
overflow: hidden;
float:left;
position: absolute;

}

и

@media screen and (max-aspect-ratio: 19/10) and (min-aspect-ratio: 17/10) { /* разрешение 16/10*/
#img1{
background: url(../images/1.1.jpg) no-repeat center center;
background-size: cover;
-webkit-background-size: cover;
-o-background-size: cover;
-moz-background-size: cover;
margin: 0;
padding: 0;
width: 100%;
height: 100%;
}

#img2{
background: url(../images/2.1.jpg) no-repeat center center;
background-size: cover;
-webkit-background-size: cover;
-o-background-size: cover;
-moz-background-size: cover;
margin: 0;
padding: 0;
width: 100%;
height: 100%;
}

#img3{
background: url(../images/3.1.jpg) no-repeat center center;
background-size: cover;
-webkit-background-size: cover;
-o-background-size: cover;
-moz-background-size: cover;
margin: 0;
padding: 0;
width: 100%;
height: 100%;
}
#img4{
background: url(../images/4.1.jpg) no-repeat center center;
background-size: cover;
-webkit-background-size: cover;
-o-background-size: cover;
-moz-background-size: cover;
margin: 0;
padding: 0;
width: 100%;
height: 100%;
}
#img5{
background: url(../images/5.1.jpg) no-repeat center center;
background-size: cover;
-webkit-background-size: cover;
-o-background-size: cover;
-moz-background-size: cover;
margin: 0;
padding: 0;
width: 100%;
height: 100%;
}

}