Thumbnail image inside the post "container"

Hi,
I will try to be more clearer with what I want to customize at this beautiful theme.
I just want to remove the thumbnail image as it is as default in the page. I have read how to do this and it’s not a problem, but in the same time I would like to integrate my thumbnail image for each post inside that post container/square or whatever you would like to name it.
Something like this: under the date, author, whatever, floating left at a size of 120×120 or something like this will be the post thumbnail image; and aligned with the image, at the right side would be the excerpt text.
Hope you understand my vision. I can customize the options I enumerate above, but I would like to know if there is a way to integrate my thumbnail image like this and how?

I will be forever grateful. Thank you very much!