curl::option CurlHandle,"HTTPHEADER","Accept: image/gif"
Use this option to specify a header to be sent to the server. If you add a header that is otherwise generated and used by libcurl internally, your added one will be used instead. If you add a header with no contents as in Accept:, the internally used header will just get disabled. Thus, using this option you can add new headers, replace internal headers and remove internal headers.
You should call the function with this option for each extra header line that you want to add.