Yale University just posted a HUGE photo archive; searching "plane" yielded over 900 results (lots of B-24 and B-25 factory shots), and so far there's one B-17E:
Wayne County Airport, a United States Army Air Corps air ferry command base sixteen miles from Detroit, Michigan. Workers inspecting a plane/September 1942
41-2622/FK198; per Baugher:
2622 to RAF as FK198. Struck on ground by another Fortress Apr 9, 1944. SOC.
ETA: Type "Fortress" in the search box and tons of factory shots come up, along with this nice shot of B-17F 42-5460 (nothing in Baugher, AAIR shows it as a trainer at Biggs Field, TX):
