captcha image not displaying and can't login to my site

Hello. I added the plugin “SI captcha anit spam” on 2 of my wordpress blog sites. One of them works fine. On the other one I checked the box in the plugin settings to add captcha to the login page, and now captcha won’t display and I can’t login. just my luck:) Does anyone know how I can get into my site without having to login through the domain/blog/wp-login.php thanks so much.