Insert media at new message

Hello there, I'm using the free Gridalicious theme at my Wordpress site, I'd like to upgrade to PRO, but I hope one thing can be solved, before I buy the theme... If I'm posting a new message on my site and I want to add media... I don't get a screen where I can choose/upload a picture. That's the only thing that's not working. I like this theme a lot. I hope someone can help me. Thanks in advance