No option for Thumbnails anymore?

[GraceSlick]

Hello

I haven't worked much on any sites successfully for a long time and have decided to start again. Only this time, I want to add thumbnails to each post which are visible on the homepage but...

I used to be able to do this in custom files very easily in each post (just below the text).
Yet now there is no option to do so? The new WP simply doesn't have this option?

Please can someone advise me on how I can get them back? or another method I have to do from now on to get thumbnails to show?

I am using WordPress 3.2.1.
My Site: www.allgamblingsites.com

Sorry if this has been asked before but I cannot find any help that's helped me so far.

Thank you very much for your time,

Grace