A bit confused here, featured image of every blog post can be shown automatically. You can see here on demo:
If you want to keep image just above the list of blog post then there is way you can do that:
1. Same method given on previous reply. Later you can use widgets visibility module of jetpack to hide/show on specific pages.
2.You need to customize the index.php template. Please proceed for this only if you are technically sound on WordPress otherwise you will be facing same error ie site can be down.