There are 2 ways to upload images into your WordPress site – through the post/page image uploader or through the media library.
Both place images into your overall media library; and both give you the ability to drag and drop upload multiple images at once.
So what’s the difference and which one should you use? Good questions.
Most people add images into a post using the Add/Insert button located just above the post/page editor. This gives you the ability to upload files from your computer, a web url, or from inside your media library.
It also places that file immediately inside a “Gallery” which gives you the ability to quickly choose the image for re-use later in the same post.
That’s fine if you’re working with images not already in your media library, because those images have to be uploaded anyway.
But if you run a multi-author blog, or a website that has images inside the library that you plan to reuse, attaching those images to posts using the media library is the more efficient way to go.
Using Media Library to Attach Images to Posts and Pages
You can make images appear inside your gallery at the post and page level by using the media library.
This is also a great workflow option for those writers who like to compose blog posts with text first and then add images later. So rather than using the Add/Insert button at the post level and adding images from your library one by one, you can employ a more efficient method of attaching images.
When you have a post in draft form – text only, navigate to your media library and find the images you plan to use with that post, select them and then click the “Attach” link.
A modal window will popup and give you a search field where you can type text to find posts. When those posts have populated the window, select the box next to the post name, and those images will automatically be “attached” to the selected post – that is, they will be available through that post or page image gallery, and available for quick insertion into the post or page editor screen.
Once you return to that draft post, you can then insert images into the editor by using the GALLERY found inside the Add/Insert screen, rather than uploading duplicate copies, or having to search for them individually inside the media library.