Blog post picture (snapshot theme)

On my website, I get black boxes for each blogpost on my blogpage when I don’t use a featured picture. If I do use a featured picture, on each blogpost on top there is a big picture. I have a static page without the blog post slider.

Can I either get only the black box with the blog content visible immediately (so no image needed, just the title and part of the text of the blogpost) or no big picture at the top of each blogpost with a featured image?

Ans is it possible to put the picture in the middle of the black box?

Thanks a lot!