Images
To add an image to your templates, select the "Upload" button from the sidebar, click the "Upload your own images" button, and select the new image in it's location on your computer.
Click and drag the image from the sidebar into the image frame. To adjust the position of your image once it's in the frame, double-click the image frame, scale and adjust to your liking, then click the "check" icon to set it in place.