In the 
-widget, images and URLs can be inserted and played in the conversation. A preview of the image or link will be displayed in the conversation. Images, YouTube and Vimeo videos, and GIFs will be directly embedded into the conversation. The link serves as a reference. The specific kind of media type will be automatically recognized and set when inserted.
Additionally, an alternative description has to be added, which describes the image or link in a few words.
Here's a video example of how the media widget can be used:
Important: Make sure that your pictures are optimized for the web, so that they have a shorter loading time.