Well done, Ken!
This is most certainly the 17th BG flight line in Dijon Winter 1944-45, but might as well be 320th BG, too, as they were based there at same time. The design of Battle Numbers on tail would help distinguish them (scan at high res).
Anyway, I checked my 17th BG photo folder, and found a crashed B-17 photographed in Telergma, Algeria, in Spring 1943, named "Susy Q". It had a number 6 on tail (attachment). So your B-17 photo might as well be from one of the B-17 units in 12th AF 5th BW in North Africa. Possible units should be:
- 2nd BG (heavy)
- 97th BG (heavy)
- 99th BG (heavy)
- 301st BG (heavy)
As all these groups have forums here you might post at those with the photo asking for help to ID that plane.
Maybe your grandfather had some friends in one of those groups? Also found (by Google) that James Doolittle had a
B-17, too. As you know, many US aircraft were named also after movie characters etc, not just pin-ups....so your hypothesis about "FLICKA" is sound.