opt := &cos.ObjectPutOptions{
    nil,
    &cos.ObjectPutHeaderOptions{
        XOptionHeader: &http.Header{},
    },
}
pic := &cos.PicOperations{
    IsPicInfo: 1,
    Rules: []cos.PicOperationsRules{
        {
            FileId: ".jpg",
            Rule:   "watermark/3/type/3/text/" + base64.StdEncoding.EncodeToString([]byte("testwatermark")),
        },
    },
}
opt.XOptionHeader.Add("Pic-Operations", cos.EncodePicOperations(pic))
name := "test.jpg"
filepath := "./test.jpg"
res, _, err := c.CI.PutFromFile(context.Background(), name, filepath, opt)

name = "test.jpg"
filepath := "watermark.jpg"
_, err = c.CI.GetToFile(context.Background(), name, filepath, "watermark/3/type/3/text/"+base64.StdEncoding.EncodeToString([]byte("testwatermark")), nil)

opt := &cos.ObjectPutOptions{
    nil,
    &cos.ObjectPutHeaderOptions{
        XOptionHeader: &http.Header{},
    },
}
pic := &cos.PicOperations{
    IsPicInfo: 1,
    Rules: []cos.PicOperationsRules{
        {
            FileId: "format2.jpg",
            Rule:   "watermark/4/type/3/text/" + base64.StdEncoding.EncodeToString([]byte("testwatermark")),
        },
    },
}
opt.XOptionHeader.Add("Pic-Operations", cos.EncodePicOperations(pic))
name := "test2.jpg"
_, err := c.Object.PutFromFile(context.Background(), name, filepath, opt)