Here are the steps below to add the pictures directly to the post:
- Sign in to your WordPress Dashboard
- Click on Posts
- Select the Post you want to edit and click on Edit
- Click on Set featured image and upload the image you want to show separately on your Post
- Once the file will be uploaded, click on Insert into Post, the image will show up in the Upload/Insert box.
- Then click on Update on the right hand side in the sidebar and refresh your website.
Note: You can't create one gallery and post some of the images from that gallery in one place, and the other images from the same gallery in other place. You will need to create more than one gallery in order to do that.