Attachments – any files uploaded to your WordPress website. We call them attachments because when you upload a file directly from post edit pages, the file will be attached to the appropriated post.

Custom Gallery Metabox

Featured Images in Quick Edit

How to Add Images to Media Library after Uploading them in PHP Programmatically

How to to Add a Custom Media Uploader Button in WordPress Admin

Custom HTML template for images you insert in posts

How to Create a Slider for Images In Posts