Someone asked how arrows are placed in a pic to identify something. You can do this in your "Edit" page. Simply click on the arrow type you would like to use. You can also select a color from the color chart at right. Next, left click mouse at the location the arrow is to be used. You can manipulate the arrow into almost any configuration by simply dragging your mouse. Each arrow is directional (left, right, up & down).
I use the "Diagonal Line" at the upper left to make my own arrows for tight areas.