I discovered this feature some days ago, while tweaking the publish options. It’s not available directly, but it can be done.

So, to upload a video, you have to select what kind of post you want to publish. In this case, select photo, or picture (I have it in Spanish, so I can see “fotografía”). Next, in the URL box, where it says “photo”, you change it to “video”. You press enter, and that’s it.

Obviously, you have to copy/paste the URL where the video is hosted, but after that, you see a thumbnail of the video and the description. However, I don’t know about publishing videos from your computer like you can do with photos.