Create an album in your Photo Manager and name it Homepage for example.
Either upload the images you would like to have in this Album, or copy them from another Album.
Once you have created and filled your Homepage album, drag it into the Client albums section.
This will prevent it from appearing in your overall portfolio.
Pixelrights > Dashboard > Design Manager > Homepage > Edit homepage > Background.
On the left will be a drop down menu, allowing you to select which images you wish to display on your hompage.
Your newly created 'Homepage' album will appear for you to select.
Save this change and preview your new background slideshow.
Please be aware that some images may result in cropping.