Это пример кода с использованием HttpClient.
Надеюсь, эта информация поможет вам.
// yourID
String userID = "";
String albumID = "";
String photoID = "";
HttpPost postRequest = new HttpPost(
"https://picasaweb.google.com/data/feed/api/user/" + userID
+ "/albumid/" + albumID + "/photoid/" + photoID);
postRequest.addHeader(new BasicHeader("GData-Version", "2.0"));
postRequest.addHeader(new BasicHeader("Authorization",
"GoogleLogin auth=" + mAuthToken));
String content =
"<entry xmlns='http://www.w3.org/2005/Atom'>"
+ "<content>" + comment + "</content>"
+ "<category scheme='http://schemas.google.com/g/2005#kind'"
+ " term='http://schemas.google.com/photos/2007#comment'/>"
+ "</entry>";
try {
StringEntity entity = new StringEntity(content);
entity.setContentType(new BasicHeader("Content-Type",
"application/atom+xml"));
postRequest.setEntity(entity);
HttpClient httpclient = new DefaultHttpClient();
HttpResponse response = httpclient.execute(postRequest);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}