Set a comment in the image store specified by handle. This sets a comment of name name to the string value. If value is omitted, then the name is saved without an empty value.
Random access image store, such as pixmaps, don't automatically clear comments if reused to store subsequent images, either through rendering or copying, Either delete and recreate the image store or delete all comments with SippCommentDelete.
If the image store does not support comments, a error is returned.