I am working on an application that requires Drag & Drop functionality in a web page with images. First I thought I would implement this using JQuery UI, because I had used it earlier and it makes DnD very easy. But then I thought it may not be too difficult to implement it myself. As it turned out, it is not really very difficult. Here is a simple demo of that implementation.
There are two Divs in this demo, one containing image thumbnails and the other is a drop target for images. Drag and drop image thumbnails on the target Div. The original image would be added to the Div.You can then move images within this Div. If you drag and drop it anywhere outside the div, the drop operation is cancelled and image is removed.