I skimmed through the guy's Twitter thread. I'm 95%+ sure that he's going so far down the rabbit hole that he's likely to exit in the antipodes. I see little to no evidence that he has a background in or understanding of photography in general, let alone the photo forensics website he tried to use or the changes in the state of the art since 2009.
And, of course, it's apparent that the photo in question
was modified in at least one regard - it's been cropped. Given the camera used, the original image would have had a 3:2 aspect ratio; the image we see is approximately square. That's almost certainly irrelevant to the core message of the picture. (I don't know about you, but aside from someone with a gun pointed at Franken's head, I can't think of any exculpatory information that would likely be contained in a cropped-out bit.)
Even today, transplanting Franken into that photo skillfully enough to pass casual examination would probably be a technological challenge. In 2009, getting the transplant right - shadow and all - would have been extremely difficult, particularly given Franken's hairstyle and the slightly fuzzy shirt he's wearing in the picture. That's almost equally true for the challenges involved in photoshopping her in - the shadow on her armor is very hard.
Eyeballing the EXIF, the image looks like it's a crop of the edge of a slightly larger picture. The lighting looks appropriate for an on-camera flash, and the slightly-grainy look on things is appropriate for an ISO in the 4000s. Both the use of the flash and the high ISO (to compensate for dim lighting) are appropriate to a dimly-lit military flight.
And as far as his use of the fotoforensics thing goes, here's something
taken directly from their website - "Similarly, saving a JPEG with an Adobe product will automatically sharpen high-contrast edges and textures, making them appear much brighter than low-texture surfaces."