Facebook is the fodder for much of the content of this site. If you’re saving the image directly from Facebook, or even getting the JPG originals from her, I’m sure you already know that successive edits to JPG files degrade the image every time. If she wants you to do more, charge her a fee for your time—how much you charge is dependent on the level of the friendship and whether or not you want to deter her from asking for more edits (or you could simply tell her no). Of course, if you like doing that kind of stuff, she could very well refer you to her friends and you could make some extra money over and above your current means. It doesn’t have to be digital files, either, there are those who would pay a lot to have old family photographs restored from cracked and faded originals.