问使用JS在CSS中删除作为背景图像的加载栏

EN

#generated {
    border: 1px solid #021a40;
    cursor: pointer;
    background: url(../images/loading400px.gif) 50% no-repeat;
}

function AsynchronouslyDownloadImage(address, img) {
    img.src = "static/images/shader.svg";
    let downloadingImage = new Image();
    downloadingImage.onload = function () {
        // This img.style.background is what I thought will make my background disappear but this isn't working
        img.style.background = "";
        img.src = this.src;
    };

    downloadingImage.src = imagesEndpoint;
    }