how did you do that?

I've been meaning to respond to you on this.

Generally, you can right click on the original image and select "Copy image address"

Now, from some sites, you will get a file with an extension like jpg or png. Those can be pasted directly into a DU post and will appear when you click "Post my reply." I'm guessing you already known Control + V will do the pasting.

In the case of Facebook, a right click followed by "Copy image address" will not give you a jpeg or png file. So you go to a third-party site -- I recommend Imgur.com and my instructions from this point will revolve around Imgur.

You go to the green "new post" button near the top left of the screen and click it. Then hit Control + V to paste your file. When the screen refreshes and your image shows up, go to the right side of the screen and click on "embed post." It will bring up your picture on a similar looking screen. Then you right click on that image and it will now be in jpg or png format so you can "Copy image address."

You bring that back to the DU post screen and drop it in here with a Control + V.

Voila, ready to post!