zulip/templates/zerver/help/upload-and-share-files.md

## Uploading and Sharing Files

Zulip allows you to easily attach files, including images, sound, and video by:

- *Clicking the Paperclip Icon* Use the paperclip icon
  (<i class="icon-vector-paper-clip"></i>) located under the
  message field.
- *Dragging* You may also drag and drop files on the message
  field. The files are uploaded to a server and a link is supplied,
  but a thumbnail is displayed if possible. The link to the file will
  be in Markdown format: `[link_text](link_URL)`

![before](/static/images/help/file_upload_before.png)

If you wish to give your image a caption or title, you may add text
before or after the generated link. Any text you add in the box will
not break the link to your file so long as the file link remains
intact.

---

After submitting your message, you will see a clickable thumbnail if
your file is a common image type (i.e. PNG, JPEG, etc.). All other
files will simply have a link displayed.

![after](/static/images/help/file_upload_after_image_preview.png)

### Link Behavior

Clicking all file links will open a new tab that will
either 1. display the file if it is an image or 2. download the file
automatically to your computer.

If the file has a thumbnail, clicking it will open a lightbox modal
with varying options depending on the media type. Images may be opened
in new tabs or downloaded, while videos from Youtube may only be
opened (and not downloaded). You can exit out of a lightbox by
clicking the space around the media preview or by clicking the exit
button found in the upper right-hand corner.


### Sharing Files from External Websites

Images and videos shared from external websites, such as Imgur or
Youtube, may have previews generated as well. Clicking previews of
images/videos from external websites will lead to the same lightbox
behavior described above.

![external](/static/images/help/file_share_imgur_preview.png)