Div içindeki resmin Div'e göre dolduğu zaman görüntü bozulması

<div class="slider-area">
                <div class="slider">
<div class="mySlides fade">
  <img src="img/slider1.jpg" alt="">
</div>

<div class="mySlides fade">
  <img src="img/slider2.jpg" alt="">
 
</div>

<div class="mySlides fade">
  <img src="img/slider3.jpg" alt="">
</div>

<div class="mySlides fade">
  <img src="img/slider4.jpg" alt="">
</div>

<div class="mySlides fade">
  <img src="img/slider5.jpg" alt="">
</div>

<a class="prev" onclick="plusSlides(-1)">&#10094;</a>
<a class="next" onclick="plusSlides(1)">&#10095;</a>

</div>
<br>

<div style="text-align:center">
  <span class="dot" onclick="currentSlide(1)"></span>
  <span class="dot" onclick="currentSlide(2)"></span>
  <span class="dot" onclick="currentSlide(3)"></span>
  <span class="dot" onclick="currentSlide(4)"></span>
  <span class="dot" onclick="currentSlide(5)"></span>
</div>
</div>
</div>

.slider-area
{
    width: 100%;
    height: 500px;
}

.slider
{
    width: 100%;
    height: 500px;
  
}
.slider img
{
    object-fit: cover;
    width: 100%;
    height: 500px;
}


/* Next & previous buttons */
.prev, .next {
  cursor: pointer;
  position: absolute;
  top: 50%;
  width: auto;
  padding: 16px;
  margin-top: -22px;
  color: white;
  font-weight: bold;
  font-size: 18px;
  transition: 0.6s ease;
  border-radius: 0 3px 3px 0;
  user-select: none;
}

/* Position the "next button" to the right */
.next {
  right: 0;
  border-radius: 3px 0 0 3px;
}

/* On hover, add a black background color with a little bit see-through */
.prev:hover, .next:hover {
  background-color: rgba(0,0,0,0.8);
}



/* The dots/bullets/indicators */
.dot {
  cursor: pointer;
  height: 15px;
  width: 15px;
  margin: 0 2px;
  background-color: #fff;
  border-radius: 50%;
  display: inline-block;
  transition: background-color 0.6s ease;
}

.active, .dot:hover {
  background-color: #717171;
}

/* Fading animation */
.fade {
  -webkit-animation-name: fade;
  -webkit-animation-duration: 1.5s;
  animation-name: fade;
  animation-duration: 1.5s;
}

@-webkit-keyframes fade {
  from {opacity: .4}
  to {opacity: 1}
}

@keyframes fade {
  from {opacity: .4}
  to {opacity: 1}
}