When you use the plugin with already created posts, you may notice that featured images in the list are small or sometimes bigger than it should be. This is because the plugin needs to create its own images size.
To fix that issue, you’ll have to regenerate your featured images.
For this to work, the original image size should be at least 650×415 (pixels)
- Download & install the plugin “Regenerate Thumbnails”.
- Active the plugin.
- Click on the menu “Tools / Regenerate Thumbnails”, then, regenerate your images.