I admit, I did exactly the same thing for my passport a couple of years ago. Considered taking my own photo and it said no shadows in the specification but the only plain wall I could use was in a position where I couldn't light the area well enough. In the end I used a photo booth and my head seemed to take up far too much of the photo, and although it wasn't within the specification on the passport application notes I sent it off and they accepted it anyway.
I don't see the issue to be honest with you -- its quick, easy, and not that expensive and its done. I doubt your time is worth the difference of doing it yourself!