Release: Dashboard Backgrounds and Transparent Tiles

It’s only the “Add Media” link from the Media Selector in the Dashboard Background setting that shows ‘coming soon’ (thanks for the reminder!). You can still manually add Media directly from your User Page and then it will show up as a selection for your dashboard background:

https://sharptools.io/user/resources/media

Note that the image would need to be hosted online somewhere. The following post has some details: