If you use a photo that has a caption attached to it, this will show on your blog summary featured image. In the event you want to disable the featured image captions as you see here:

screenshot demo showing the featured image captions
  1. Go to Appearance > Customize > Ariele Theme Options > Blog Settings.
  2. Check the box Hide the Featured Image Caption to hide the caption.
  3. Click the Publish button.
screenshot for the hide featured image caption setting