Can you therefore paste image directly into post without having to
attach file ?
You can paste images which already appear in other web pages directly into a post - just using Copy and Paste - you could do this with the old forum as well. (When you copy parts of a web page, including the image - you are really copying and pasting the HTML, there for the link to the image, links to other URLs, etc.)
However, you cannot paste images from your machine, or documents in your machine. (I always thought this would be a great browser feature - to paste an image from the clipboard rather having tosave the image to disk and upload it - but no browser seems to have done this yet.