Front End Form modification needed

Hi there, i’m trying out some event calendar pluginsandthink i found the best for my needs.

But i need some help, have been searching around but can not find any answer.

I need the possibility, on the frond end submit form for not logged in users, to add imagens to the text field. Is there any possibility?

Thanks a lot in advance.

The page I need help with: [log in to see the link]