CSS实现的图片对角凹陷插入特效代码

使用方法

body{
  background: 
    repeating-linear-gradient(30deg, #fff2 0 10%, #fff0 0 24%),
    repeating-linear-gradient(-23deg, #fff2 0 4%, #fff0 0 14%)
    gold !important;
}
figure {
  --c: 50px;
  --p: 30px;
  --d: 10px;
  background: red;
  display: inline-block;
  padding: var(--p);
  background:
    radial-gradient(farthest-side at 0 0, #000, #0000) 0 0 / var(--c) var(--c),
    radial-gradient(farthest-side at 100% 100%, #000, #0000) 100% 100% / var(--c) var(--c),
    linear-gradient(#fff 0 0) 50% 50% / calc(100% - var(--p)) calc(100% - var(--p)),
    linear-gradient(#0000, #000 25% 75%, #0000) 50% 50% / calc(100% - var(--p)) calc(100% - var(--d)),
    linear-gradient(90deg, #0000, #000 25% 75%, #0000) 50% 50% / calc(100% - var(--d)) calc(100% - var(--p)),
    radial-gradient(farthest-side at 0 100%, #00000018, #0000) calc(100% - var(--d) * 0.5) calc(var(--d) * 0.5) / var(--d) var(--d),
    radial-gradient(farthest-side at 100% 0, #00000018, #0000) calc(var(--d) * 0.5) calc(100% - var(--d) * 0.5) / var(--d) var(--d)
    ;
  background-repeat: no-repeat;
  clip-path: polygon(0 var(--c), var(--c) 0, 100% 0, 100% calc(100% - var(--c)), calc(100% - var(--c)) 100%, 0 100%);
}

/* demo */
figure:nth-of-type(1) img {
  width: 300px;
}

figure:nth-of-type(2) img {
  width: 300px;
  height: 200px;
}

figure:nth-of-type(3) img {
  width: 300px;
  aspect-ratio: 1;
}

.cd__main {
  background: 
    repeating-linear-gradient(30deg, #fff2 0 10%, #fff0 0 24%),
    repeating-linear-gradient(-23deg, #fff2 0 4%, #fff0 0 14%)
    gold !important;
}

img {
  object-fit: cover;
}