Thumbnail for Blog Post does not appear

I can not get the thumbnail image to appear on my home page in the blog post from a user submitted form I created in gravity forms. here is the link to my blog post page: http://changingurworld.com/wp2/2011/07/27/my-heart/

I also do not want it o display the user name and category under the title.

And how do I get rid of the comment on the bottom: “Sorry, the comment form is closed at this time.” I am not allowing comments.

Thank you.