Graphics or other pictures in the message, not an attachment

[MMcK]

In my roundcube compose screen I see an icon for a graphic or picture. When I click on it, it tells me to insert the URL for the graphic.  How do I get a url for a graphic, such as a .jpg?

[SKaero]

The image needs to be hosted online and then you can get url when view the image (just the image) from the url bar of the browser.