Drag and drop is a simple way to allow users to upload their files by dropping them into the container. Nowadays most websites allow uploading using both drag and drop and the file browse e.g. PushBullet, Facebook, SlideShare, etc.
I am using AJAX to save the file to the server which triggers when the file dropped on the target container.
In this tutorial, I show how you can implement a similar type of feature in your project and show a thumbnail when the file is successfully uploaded using jQuery AJAX and PHP.