PutObjectRequest request = new PutObjectRequest(bucket, key, srcPath);

JObject o = new JObject();
// Do not return the input image
o["is_pic_info"] = 0;
JArray rules = new JArray();
JObject rule = new JObject();
rule["bucket"] = bucket;
rule["fileid"] = key;
// Processing parameters. For rules, visit https://www.tencentcloud.com/document/product/436/46782?from_cn_redirect=1.
rule["rule"] = "watermark/3/type/<type>/image/<imageUrl>/text/<text>/level/<level>";
rules.Add(rule);
o["rules"] = rules;

string ruleString = o.ToString(Formatting.None);
request.SetRequestHeader("Pic-Operations", ruleString);
// Execute the request
PutObjectResult result = cosXml.PutObject(request);

GetObjectRequest getObjectRequest = new GetObjectRequest(bucket, key, localDir, localFileName);
// Processing parameters. For rules, visit https://www.tencentcloud.com/document/product/436/46782?from_cn_redirect=1.
getObjectRequest.SetQueryParameter("watermark/3/type/<type>/image/<imageUrl>/text/<text>", null);

GetObjectResult result = cosXml.GetObject(getObjectRequest);