How to fill inside a selection when the inside is transparent
I have a .png image which is a line drawing of a leaf. I want to fill the inside of leaf with a color. I would like the color not to be totally opaque in order to see the lines inside the leaf. I can select the outside border of the leaf but I simply cannot find the answer to how to create a fill of color inside the leaf (inside the selection). The problem seems to be that what I consider the "inside" of the leaf is transparent and so isn't part of the selection. I have searched and searched on-line to no avail for how to create that fill. I will be very grateful for any help!

