Need “feature image” help, plugin, or code

Okay so I started to make my own custom theme for my hardware review site. Everything is going great until I run into a problem. If you look at the design, link listed below, you can see that there is a “featured image” on the review. I’ve searched on these forums, and on google a million times over for something. Only thing that came close was a custom “featured art” plugin made by TheUberGeeks for their site.
https://www.deviantart.com/view/32715180/

What I need is to be able to specifiy which image will go there per review, per user logged in. I’m not the only review writer, so the other users need to be able to post the “featured image” as well. I have tried a couple of plugins with no luck getting them to work for what I need. I’m no PHP coder, otherwise I would have had this already done. I’ve been reading up on using the Custom Fields options in the Admin, but from what I did it only posted text per review. I would just like some help to point me in the right direction to make a featured image plugin that I can upload an image from the Write Post section.

So far i’ve tried Image2Post, The Feature, and Select Metadata from the Kiwi development. None of those wanted to work for what I needed. I’m just so lost as what to do. Any help would be great. Thanks.