As a Pro user or Business user, you are able to upload your own photos and wallpapers to customize both your dashboard and your project boards.
Change The Background Image on Your Dashboard:
To change the background image in your dashboard, click the little wheel icon underneath the time and quote. This will open the backgrounds menu.
Click the Upload button underneath Custom Photos and select an image from your computer.
Once the picture has finished uploading, click on it to update the dashboard background.
Change The Background Image in a Project:
Open the project and click the ( i ) button in the top bar. From the dialog that appears select Change Background...
Click the Upload button underneath Custom Photos and select an image from your computer. As soon as the picture is uploaded successfully, click the picture to update the background of your project.