The patterns on the 40 and 70 year old triathlete match far too well. I'm calling bullshit. The "70 year old triathlete" scan is just further up the leg of the 40 year old.
Now have you noticed carbon atoms are strikingly similar? Good, almost there.
Somewhere in-between these two views unique features emerge. Tell me where on the scale of atom to human the quads are? There is plenty in these pictures that is unique in the two persons depicted.
There is no need to lie to make a good argument for exercise. This image belong on your grandmothers Facebook page at best.
That's why discriminating readers (like us) should rigorously overlook pretty pictures and instead look only at: 1) the amount of separation between groups (big effect?), 2) the stat. significance across the given population (consistent signal?), 3) the constraints the authors used to create that population (representative of the real world?), and 4) whether the discriminating signal they chose selectively detects the causal effect they propose.
No picture can do all of that.