golang替换字符串中的图片链接，如何提升性能呢？

给定字符串

content="<span class=""><img class="wscnph" src="https://static.images.net/202233142551646287375.jpg"><img class="wscnph" src="https://static.images.net/202233142551646287377.jpg"></span>"

使用正则匹配图片链接，然后上传图片到阿里云oss,获得图片的链接，然后替换字符串中图片的链接，如果给定的字符串中图片很多，怎样才能提高图片上传替换的速度

func Upload(url string) string {
    // 创建OSSClient实例。
    client, err := oss.New(Endpoint, key, AccessKeySecret)
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }
    t1 := time.Now().Unix()
    if ti1 != t1 { //如果时间戳不一样,那么归零
        long = 0
    }
    ti1 = t1
    long++
    obj := fmt.Sprintf("article/%d%d.png", t1, long)
    // 获取存储空间。
    bucket, err := client.Bucket(BucketName)
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }

    // 上传Byte数组。
    err = bucket.PutObject(obj, bytes.NewReader(ReadImgData(url)))
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }
    return "https://" + BucketName + "." + Endpoint + "/" + obj
}
func RepImages(htmls string) string {
    var imgRE = regexp.MustCompile(`<img[^>]+\bsrc=["']([^"']+)["']`)
    imgs := imgRE.FindAllStringSubmatch(htmls, -1)
    out := make([]string, len(imgs))
    myImage := ""
    resHtml := htmls
    for i := range out {
        if ! strings.HasPrefix(imgs[i][1], "https://static.images.net") {
            myImage = Upload(imgs[i][1])
            resHtml = strings.Replace(resHtml, imgs[i][1], myImage, -1)
            out[i] = imgs[i][1]
            fmt.Println(strconv.Itoa(i), out[i])
        }
    }
    fmt.Println(resHtml)
    return resHtml
}

func main() {
    //a := BcryptHash("admin123$")
    //fmt.Print(a)
    content := "<span class=\"\"><img class=\"wscnph\" src=\"https://static.images.net/2022331359421646287182.jpg\"><img class=\"wscnph\" src=\"https://static.images.net/202233135942164628718777.jpg\"></span>"
    RepImages(content)
}