It is always recommended to add featured image in your posts and pages. Our themes are highly dependent on featured images.
Setting Featured Image
1. Open the editor of the post/page where you want to display image, and locate the Featured Image module in the bottom right corner under Page Attributes. Click on Choose a Featured Image.
2. Then you can either upload the image from your computer or select the existing image from your media library and click on Set Featured Image.
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