Auto blog not pulling in correct image

Hi I have autoblog across some sites. My main site mywikaniko.com effectively collates lots of different feeds, I then curate and publish to a single “master” feed. My subdomains then auto publish from the rss – the issue I am having is that each post has a featured image, but the subdomains are not pulling in the correct one as it is not always the first pic on the post

Which setting should I be using on the featured image add-on?

You can see the Master Blog result here https://mywikaniko.com/ (slider at top is the pertinent bit) and you can then see the different version on a sub domain here http://wikaniko.net (the drought post hasnt pulled in a photo at all)

I am currently using media thumbnial setting (which doesnt work!) so advice would be appreciated. As is my rss feed I can set the master feed up in any way neccesary

Thanks