在具有Captcha的不同站点上向多个表单发送请求

I want to make a multi registration form that posts on multiple sites the user doesn't need to type the same data over and over but he will post it on this form.The problem is that some sites may have captcha so I need a way to retrieve the captcha image on my form using cookies,sessions, curl I don't know which method can help me.I want to make a multi registration form that p