Download images by clicking on them and as they zoom, you'll be able to drag it from the chat window and drop it to your prefered location.
Send images by droping them to the chat window, but there are certain locations where it does not work (ie. Photos). As a workaround you need to drop such images to a temporary locations (ie. Desktop) and drag it from there.
Sending videos are limited to size and format: maximum 16mb and mp4 format.
We're sorry that recently this features are quite limited, but we'll try to improve it soon.