您可以使用以下概念：

1. 使用 Object.values 将图片转换为数组，然后对数组进行打乱。

// see shuffle options in the snippet
const data = shuffle(Object.values(pictures));

2. 由于数据现在已打乱，只需使用 array.slice 从数组中获取前 3 个项目即可。>

const selected = data.slice(0, 3);

如果您使用 Flavios Copes 排序，则可以在一行中完成此操作随机播放：

const selected = Object.values(pictures).sort(() => Math.random() - 0.5).slice(0, 3);

const pictures = {
  0: {
    "src": "Images - Copy/crack_plant.jpg",
    "alt": "Seedling growing through bricks"
  },
  1: {
    "src": "Images - Copy/desert_botanical.jpg",
    "alt": "Phoenix's Desert Botanical Garden"
  },
  2: {
    "src": "Images - Copy/LookUp.jpg",
    "alt": "Looking up through forest"
  },
  3: {
    "src": "Images - Copy/LookUpLeaves.jpg",
    "alt": "Looking up at leaves"
  },
  4: {
    "src": "Images - Copy/Road_Through_Trees.jpg",
    "alt": "A path covered by trees"
  },
  5: {
    "src": "Images - Copy/Sand.jpg",
    "alt": "Tiny balls of sand formed by crabs"
  },
  6: {
    "src": "Images - Copy/Snow.jpg",
    "alt": "Powder day at Breckenridge"
  },
};

// shuffle array using Durstenfeld shuffle algorithm 
function shuffle(array) {
  for (let i = array.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [array[i], array[j]] = [array[j], array[i]];
  }

  return array;
}

// convert to an array and shuffle
const data = shuffle(Object.values(pictures));

// grab the first 3
const selected = data.slice(0, 3);

console.info(selected);

// one liner using Flavios Copes sort 
console.info(Object.values(pictures).sort(() => Math.random() - 0.5).slice(0, 3));

好的，首先，您不需要具有数字键的对象。这本质上是一个数组。与对象相比，数组可以更简单地为您提供所需的功能。

您只需要使用 while 循环来检查它刚刚从数组中挑选的随机图像是否已经是挑选的图像，您可以通过单独存储生成的随机图像来做到这一点。

let pics = document.querySelectorAll(".img-fluid");
let chosenNums = [];

let getRandom = () => { 
    return Math.floor(Math.random() * pictures.length);
}

// An object with sequential numbers for keys is essentially an array
// so just use an Array.
const pictures = [
    { "src" : "Images - Copy/crack_plant.jpg", "alt" : "Seedling growing through bricks"},
    { "src" : "Images - Copy/desert_botanical.jpg", "alt" : "Phoenix's Desert Botanical Garden"},
    { "src" : "Images - Copy/LookUp.jpg", "alt" : "Looking up through forest"},
    { "src" : "Images - Copy/LookUpLeaves.jpg", "alt" : "Looking up at leaves"},
    { "src" : "Images - Copy/Road_Through_Trees.jpg", "alt" : "A path covered by trees"},
    { "src" : "Images - Copy/Sand.jpg", "alt" : "Tiny balls of sand formed by crabs"},
    { "src" : "Images - Copy/Snow.jpg", "alt" : "Powder day at Breckenridge"}
]; 

// Keep looping until we have 3 randoms
while(chosenNums.length < 3){
  let random = getRandom();  // Get a random
  // Check to see if the random is NOT already in the output array
  if(!chosenNums.includes(random)){
    chosenNums.push(random); // It's not so add it
  }
}

// Now that the output array has 3 randoms in it, loop over them
chosenNums.forEach(function(num, index){
  // Set up the img element corresponding to the loop index
  // with the data from the picture corresponding to the index
  // in the array of randoms
  pics[index].src = pictures[num].src;
  pics[index].alt = pictures[num].alt;  
});

<div class="container">
   <div class="row">
     <div class="col">
        <img id = "photo1" class="img-fluid">
     </div>
     <div class="col">
        <img id = "photo2" class="img-fluid">
     </div>
     <div class="col">
        <img id = "photo3" class="img-fluid">
     </div>
  </div>
</div>