How to Add an image from Media Library
The media Library is the place where you can find images, videos, files, and other types of media for your website.
To add media files to your Media Library, click the Add Media button on the upper left corner of the Content Toolbar.
If you already had an image into your Media Library that you would like to put into your post, simply click “Add Media” in your editor. Word press gives you the option to upload your own media. But if you click over to the next tab, you have access to all your previously uploaded content in your media library, just select the image you want, adjust the setting tab you like and click “Insert into post”. Your image will automatically be added to wherever your cursor was in the post. Hit “Preview” to see what your post will look like or hit “Publish” to make your post public.