To set a custom featured image in the MagPress theme, you’ll need to use a featured built into WordPress called: custom fields.
Set the custom field key and value
When creating a post, use the custom field key named: Featured Image. Make sure you use the key “Featured Image” (without quotes) exactly, or it may not work. Removing the space or setting characters to lowercase may cause this feature to simply not work. For the value, type in the image name located in the /featured/ directory of the MagPress theme. This will look something similar to this: http://www.example.com/wp-content/themes/MagPress/images/featured/
In the example I used an image called tech-blue.png. This can be named anything, as long as it’s in the proper directory.
Upon publishing this post in your featured category, this custom image you defined will be displayed as you see it on the demo.