js如何判断图片加载完毕

var img = new Image();
img.src = 'path/to/image.jpg';

img.onload = function() {
    console.log('图片加载完成');
};

img.onerror = function() {
    console.error('图片加载失败');
};

var img = new Image();
img.src = 'path/to/image.jpg';

img.addEventListener('load', function() {
    console.log('图片加载完成');
});

img.addEventListener('error', function() {
    console.error('图片加载失败');
});

var img = new Image();
img.src = 'path/to/image.jpg';

if (img.complete) {
    console.log('图片已加载完成');
} else {
    img.onload = function() {
        console.log('图片加载完成');
    };
}

function loadImage(url) {
    return new Promise((resolve, reject) => {
        const img = new Image();
        img.src = url;
        img.onload = () => resolve(img);
        img.onerror = reject;
    });
}

loadImage('path/to/image.jpg')
    .then(() => console.log('图片加载完成'))
    .catch(() => console.error('图片加载失败'));