The captcha appears at lake is Google's ReCaptcha. Google add these images from time to time just to comfuse bots. Its temporary. So i guess it doesn't have to do with the site.

Feedback about new captcha at mining area.
Its really fast and easy as everyone said before. So far it works very good. 
The only time that didn't work is when i forget the page open without submiting the answer. If i come back later and refresh the page and type the captcha, i ll get the "wrong captcha" error, although i typed the right answer. In that case the system gives me a fresh new captcha which works perfect. I guess its a minor problem but had to post it for the feedback if that helps.