When using the LeadLabs website builder, there will be opportunities for you to upload your own media files; including the background image and within media blocks.
When uploading an image, you will be faced with an upload panel as below.
Drag and Drop:
You can bring an image file from your desktop or a folder on your computer by manually dragging and dropping the file into the upload panel.
To manually upload an image, click the Select File button and then chose the relevant image from your computer files.
Pro-Tip: If uploading to a media block, you can then use the image to create a link.