How is a family tree usually represented?
Typically a box or rectangle is used to represent your relatives, but you can use any shape that you want to use. Each shape is a leaf on the tree. The shape you decide to use as leaves should be consistent and sized to include the information that you plan to put on your family tree chart.
What is the best format for a family tree?
While it's not as well known as some other image formats, the TIFF, or Tagged Image File Format, is by far the best choice for long-term, archival quality storage of your scanned genealogy images.