Bootstrap carousel resizing image

The reason why your image is resizing which is because it is fluid. You have two ways to do it:

1. Either give a fixed dimension to your image using CSS like:

   .carousel-inner > .item > img {
     width:640px;
     height:360px;
   }

2. A second way to can do this:

   .carousel {
     width:640px;
     height:360px;
   }

Put the following code in your CSS, this works with Bootstrap 4:

.w-100 {
  width: 100% !important;
  height: 75vh;
}

add this to your css:

.carousel-inner > .item > img, .carousel-inner > .item > a > img {
    width: 100%;
}